RECENT LITERATURE

Last update 06 November 2000

NolL of Rhizobium sp strain NGR234 is required for O-acetyltransferase activity.
Berck, S.; Perret, X.; Quesada-Vincens, D.; Prome, J.C.; Broughton, W.J.; Jabbouri, S. 1999. Journal of Bacteriology181:957-964.

Following (iso)flavonoid induction, nodulation genes of the symbiotic nitrogen-fixing bacterium Rhizobium sp. strain NGR234 elaborate a large family of lipooligosaccharidic Nod factors (NodNGR factors). When secreted into the rhizosphere of compatible legumes, these signal molecules initiate root hair deformation and nodule development. The nonreducing glucosamine residue of NodNGR factors are N acylated, N methylated, and mono- or biscarbamoylated, while position C-6 of the reducing extremity is fucosylated. This fucose residue is normally 2-O methylated and either sulfated or acetylated, Here we present an analysis of all acetylated NodNGR factors, which clearly shows that the acetate group may occupy position C-3 or C-4 of the fucose moiety. Disruption of the flavonoid-inducible nolL gene, which is preceded by a nod box, results in the synthesis of NodNGR factors that lack the 3-O- or 4-O-acetate groups. Interestingly, the nodulation capacity of the mutant NGR Omega nolL is not impaired, whereas introduction of the nod box::nolL construct into the related strain Rhizobium fredii USDA257 extends the host range of this bacterium to Calopogonium caeruleum, Leucaena leucocephala, and Lotus halophilus. Nod factors produced by a USDA257(pnolL) transconjugant were also acetylated. The nod box::nolL construct was also introduced into ANU265 (NGR234 cured of its symbiotic plasmid), along with extra copies of the nodD1 gene. When permeabilized, these cells possessed acetyltransferase activity, although crude extracts did not.

********************

The maize transcription factor Sn alters proanthocyanidin synthesis in transgenic Lotus corniculatus plants.
Damiani, F.; Paolocci, F.; Cluster, P.D.; Arcioni, S.; Tanner, G.J.; Joseph, R.G.; Li, Y.G.; de Majnik, J.; Larkin, P.J. 1999. Australian Journal of Plant Physiology 26:159-169.

Lotus corniculatus L. plants were transformed with Agrobacterium rhizogenes binary vector carrying the maize Sn regulatory gene driven by the 35S promoter. These plants showed modifications in the pattern of accumulation of proanthocyanidin (PA). All the transformed plants but one showed an increase in PA content in the root relative to control untransformed and control gus gene transformed plants (C). With respect to the PA accumulation in leaves, Sn transgenic plants were grouped in two classes: suppressed (S), that showed a consistent reduction of foliar PA content, and unsuppressed (U) that did not differ significantly from controls. Dihydroflavanol reductase (DFR) and leucocyanidin reductase (LAR) enzyme activities in S and U plant leaves mirrored the changes seen with foliar PA accumulation. LAR activity in the roots was consistent with the root PA levels. Mature Sn mRNA accumulated in the leaves of U plants, but not in leaves of S plants; however, leaves of both S and U plants were able to initiate Sn transcription. All Sn-transformed plants accumulated Sn message in root tissue. A possible negative interaction of Sn and an unidentified homologous endogene is proposed for explaining the behaviour of S plants.

********************

Companion crops for legume establishment: Forage yield, quality, and establishment success.
Wiersma, D.W.; Hoffman, P.C.; Mlynarek, M.J. 1999. Journal of Production Agriculture 12:116-122.

Alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and birdsfoot trefoil (Lotus corniculatus L.) are the predominant forage legumes grown in the north central USA. Frequently these legumes are established with a companion crop to increase establishment year forage yield, reduce erosion, and suppress weeds. Information comparing forage yield, quality, and legume establishment using traditional companion crops of oat (Avena sativa L.) and oat+field pea (Pisum spp.) vs. annual ryegrass (Lolium spp.) and festulolium (Festulolium braunii K.A.) companion crops is limited. This study was conducted to evaluate establishment year forage yield, quality and legume establishment success using five establishment methods. Four companion crops (oat, oat + field pea, annual ryegrass, festulolium) were sown with either alfalfa, red clover, or birdsfoot trefoil at two Wisconsin locations in 1993 and 1994. Each legume species was also established alone. Plots were harvested initially based on companion crop maturity and additional summer harvests were made when legumes reached mid-late bud stage of growth. Establishment year forage yields were higher when a companion crop was used than when the legume was solo seeded. At Ashland, WI, oat + field pea companion crop-legume mixtures were highest yielding in both years, averaging 0.60 ton dry matter (DM)/acre more than solo seeded legumes in the establishment year. At Marshfield in 1993 annual ryegrass and festulolium companion crop-legume mixtures yielded 0.65 ton DM/acre more than oat or oat + field pea companion crop-legume mixtures and 1.05 ton DM/acre more than solo seeded legumes. All companion crop-legume mixtures were equal, but higher yielding than solo seeded legumes in 1994 at Marshfield. Birdsfoot trefoil plots were consistently lowest yielding at both locations, except Marshfield in 1994 when alfalfa growth was suppressed due to excess moisture. Forage quality was directly related to the legume content of the harvested forage. Among the companion crops, annual ryegrass and festulolium were most frequently the highest in CP and lowest in acid detergent fiber (ADF) and neutral detergent fiber (NDF). Using annual ryegrass or festulolium as a companion crop for legume establishment may enhance the overall quality of forage harvested in the seeding year as compared with oat companion crops, and will increase yield over solo seeded legumes. In years that favor aggressive ryegrass growth, legumes may establish more slowly and may not produce as much forage in the year after establishment.

********************

Effect of condensed tannins in birdsfoot trefoil (Lotus corniculatus) and sulla (Hedysarum coronarium) on body weight, carcass fat depth, and wool growth of lambs in New Zealand.
Douglas, G.B.; Stienezen, M.; Waghorn, G.C.; Foote, A.G.; Purchas, R.W. 1999. New Zealand Journal of Agricultural Research 42:55-64.

The effects of dietary condensed tannins (CT) on growth and performance of young male weaned lambs were measured during a 4-month grazing trial when either birdsfoot trefoil (Lotus corniculatus) cv. Grasslands Goldie or sulla (Hedysarum coronarium) cv. Grasslands Aokau were fed. Each legume was offered at restricted and an libitum allowances and the effects of CT were determined by giving half the lambs in each treatment a twice-daily drench of polyethylene glycol (PEG; mol wt 3350) to deactivate the CT. Both agronomic and animal performance characteristics were recorded. Sulla had higher (P < 0.01) pre-grazing herbage masses than birdsfoot trefoil (11.6 cf. 7.1 t DM ha^-1) and sulla stem (<6 mm diam.) was eaten, in contrast to birdsfoot trefoil where stem was rejected by the lambs. The sulla and birdsfoot trefoil diets had similar protein concentrations in the DM, but sulla had a higher concentration of total CT (88 cf. 50 g CT kg^-1 DM) and less structural carbohydrate (189 cf 328 g kg^-1 DM) relative to birdsfoot trefoil. Lambs fed sulla had a similar performance to those grazing birdsfoot trefoil at restricted allowances, with average liveweight gains of 168 g d^-1. At ad libitum allowances liveweight gains averaged 273 g d^-1, but the CT in sulla reduced carcass weight from 21.2 kg (with PEG drenching) to 18.8 kg (P < 0.05). The CT in birdsfoot trefoil did not affect wool growth, liveweight gain, or carcass characteristics. The trial has shown that both forages are able to provide a high level of productivity, but the CT in sulla can be detrimental to carcass yield from young lambs given this forage as a sole diet for a prolonged period. However, the sulla produces substantially more DM and is better utilised by lambs than birdsfoot trefoil, and is able to sustain high levels of animal production per hectare.

********************

Assessing trace element uptake by vegetation on a coal fly ash landfill.
Woodbury, P.B.; Rubin, G.; McCune, D.C.; Weinstein, L.H.; Neuhauser, E.F. 1999. Water Air and Soil Pollution 111:271-286.

Improved methods are required to assess the risks posed by the uptake of potentially toxic elements such as selenium (Se), boron (B), and molybdenum (Mo) by vegetation on contaminated sites. In order to develop such methods and assess risk, vegetation was collected from two sites on a soil-capped coal fly ash landfill near Dunkirk, New York, during June of 1991 and June and August of 1992. The mean concentrations (mu g g^-1) dry weight) of Se and Mo in the shoots did not exceed, respectively, 0.12 and 18.7 in bird's-foot trefoil (Lotus corniculatus L.), 0.06 and 12.1 in red clover (Trifolium pratense L.), 0.07 and 5.3 in timothy (Phleum pratense L.), and 0.09 and 2.2 in a mixture of grasses. These concentrations were greater than those in the same species harvested concurrently from a non-landfill site. The mean concentrations of B at the landfill ranged from 29 to 53 mu g g^-1 in the legumes and from 2 to 11 mu g g^-1 in the grasses, less than those at one non-landfill site but greater than those at another. Within the landfill, the concentration of Se in grasses was not correlated with the concentration of Se in soil and fly ash. The concentration of Se in grasses on both landfill sites was double that of grasses on the non-landfill site despite higher mean concentrations of Se in the upper soil (0-15 cm) on the non-landfill site. Therefore grass roots seem to be accessing Se from the ash by means of mass flow or other mechanisms. Based on our findings of significant variation in trace element uptake among species, harvests, and locations within sites, we recommend that contemporaneous transect sampling of at least two species be used to assess uptake of potentially toxic trace elements on landfills or other sites where contamination may occur.

********************

Seed production of Lotus uliginosus cv. Sharnae in response to plant population density.
Arango, N.; Jacobs, B.C.; Blumenthal, M.J. 1998. Australian Journal of Experimental Agriculture 38:837-842.

An experiment was carried out under irrigation in the field to determine the influence of plant population density (7.5, 15, 30 and 60 plants/m(2)) on growth, development and yield of the pasture legume Lotus uliginosus cv. Sharnae. Reproductive development (flowering, pod set and stages of pod development) was recorded from 79 days after establishment and harvests were taken on 3 occasions during pod development: 118, 138 and 158 days after establishment. At each harvest, plants were divided into leaf, stem and pods. The pods were further separated into maturity classes on the basis of colour, and seed number and weight measured for each class. Harvesting late (i.e. 158 days after establishment) maximised seed yield (113 g/m(2)) and seed quality (27% immature, green pods). Seed yield per unit area up to 158 days after establishment was relatively insensitive to plant population up to 60 plants/m(2) because the response of individual plants of lotus was highly plastic. At 158 days after establishment, dry matter per plant declined from 985 g at 7.5 plants/m(2) to 713 g at 60 plants/m(2). At the same time, seed number per plant and seed weight per plant were reduced from 27400 to 3230 seeds and from 15.5 to 1.65 g, respectively, across the range of population densities. Despite the lack of a clear optimum plant population for maximum seed yield, some aspects of seed quality declined at high population density. For example, single seed weight fell by about 10% from 0.563 mg and the proportion of the harvest contributed by seeds from immature pods rose from is to 33%, as population density increased from 7.5 and 60 plants/m(2) Seed quality and ease of management, rather than yield, may be the most important considerations when seed growers choose a sowing rate for a L. pedunculatus cv. Sharnae seed crop.

********************

Comparative performance of enterobacterial repetitive intragenic consensus polymerase chain reaction and lipopolysaccharide electrophoresis for the identification of Bradyrhizobium sp. (Lotus) strains.
Santamaria, M.; Agius, F.; Monza, J.; Gutierrez-Navarro, A.M.; Corzo, J. 1999. FEMS Microbiology Ecology 28:163-168.

We compared two methods for typing bacterial strains: electrophoretic lipopolysaccharide profiling and genomic fingerprinting by enterobacterial repetitive intragenic consensus-polymerase chain reaction. Our aim was to assess the relative utility of these techniques for identification of bradyrhizobia. A collection of Uruguayan Bradyrhizobium strains isolated from Lotus subbiflorus was selected to test both techniques in terms of their discriminating ability and ease of use. Both techniques were found to be equally discriminating and they classified the samples in the same way, although each method ascribed two strains to different groups. Genomic profiling of some strains required previous DNA purification, whereas this was found to be unnecessary for others. Lipopolysaccharide profiling was found to be easier and cheaper to perform, but was not useful for determination of the genetic relationship among the strains.

********************

Effect of Euphorbia esula on sheep rumen microbial activity and mass in vitro.
Roberts, J.L.; Olson, B.E. 1999. Journal of Chemical Ecology 25:297-314.

Most large herbivores avoid the invasive weed leafy spurge (Euphorbia esula L.), possibly because the plant contains secondary compounds including terpenoids and condensed tannins. On the other hand, E. esula has high nutritive value based on traditional measures such as crude protein, fiber, and dry matter disappearance and is consumed by sheep and goats. Our objective was to determine if material from undefoliated and previously defoliated E. esula shoots, mixed in different proportions with grass hay, adversely affects sheep rumen microbial activity and mass in vitro. Material from undefoliated and previously defoliated E. esula shoots was collected in June, July, and August 1994 near Grass Range, Montana. Usually, increasing levels of E. esula leaves and powers in the mixtures increased in vitro dry matter and neutral detergent fiber disappearances (DMD, NDFD), microbial gas production, and microbial purine concentrations. In contrast, increasing levels of E. esula stems in the mixtures decreased DMD, NDFD, microbial gas production, and microbial purine concentrations. Rumen microbial gas production and purine concentrations were higher with leaves from previously defoliated than undefoliated shoots. In contrast, rumen microbial gas production and DMD were lowest for stems from previously defoliated shoots; these responses correlated with high concentrations of condensed tannins in stems of previously defoliated plants. In early summer, the high nutritive value of E. esula appears to offset any potential negative effects associated with secondary compounds. In late summer, microbial response appears more sensitive to the presence of secondary compounds, when nutritive value of this plant is declining.

********************

The effects of antinutritional factors in legume seed and rapeseed on ruminant nutrition.
Hill, G.D.; Tamminga, S. 1998. Recent Advances of Research in Antinutritional Factors in Legume Seeds and Rapeseed 93:157-172.

Legume seeds and rapeseed meal provide an excellent potential source of protein supplement for the diet of ruminant animals. Unfortunately most legume seeds contain at least one antinutritional factor (ANF) such as alkaloids, lectins, tannins, and trypsin inhibitors. Because of detoxification in the rumen the negative effects of most ANF are less severe in ruminants than in non ruminants. Tannins at low levels may even show positive responses. Other legume seeds such as peanuts (Arachis hypogaea) and soya beans (Glycine max) can produce sever allergenic reactions in animals that are exposed to them. However, the literature indicates that only preruminant calves appear to have problems from the development of antigens to soya protein. Extracted rapeseed (Brassica spp) meal from some cultivars can contain significant levels of glucosinolates. These compounds, which are goitrogenic, are apparently not destroyed in the rumen. Trials have shown that they can affect both thyroxine and trioodiothyronine levels in the blood. Further, histological effects of goitrogenicity on the thyroid glands of rapeseed fed ruminant animals have been observed. This paper reviews recent developments on the impact of these factors on the nutrition of ruminant animals.

********************

Flooding tolerance in five populations of Lotus glaber Mill. (syn. Lotus tenuis Waldst. et. Kit.).
Vignolio, O.R.; Fernandez, O.N.; Maceira, N.O. 1999. Australian Journal of Agricultural Research 50:555-559.

Lotus glaber Mill. is a herbaceous legume, tolerant to flooding, that in a few decades has colonised the Flooding Pampa grasslands, an extensive wetland of 90 000 km(2) in central-east Argentina. In this study, the growth and nodulation of flooded plants in 5 local populations were evaluated. Thirty-day-old seedlings, grown in pots, were flooded outdoors during 4 months. Stem, leaf, and root biomass, as well as the number of nodules per plant, were lower in flooded plants than in non-flooded ones. In flooded plants, the submerged portions of stems were hypertrophied and populations differed in the proportion of plants with adventitious roots. Flood tolerance was significantly related to the proportion of plants with adventitious roots in stems of each population. A positive relationship was shown between the proportion of plants with adventitious root and number of nodules per plant. The plants were also tolerant of low temperatures and ice-sheeting of water. These results underline the importance of morphological adaptations related to the maintenance of plant functionality under flooding conditions. The results provide evidence of the existence of characters related to flooding tolerance, which should be taken into account in ecological studies and agronomic selection programs.

********************

Birdsfoot trefoil seed production: I. Crop-water requirements and response to irrigation.
Garcia-Diaz, C.A.; Steiner, J.J. 1999. Crop Science 39:775-783.

Forage legume seed crop reproduction can be modified by regulating soil-water availability. However, responses to water stress differ for each species, so a single optimal water management strategy is not available for all crops. The objectives of this research were to determine the crop-water requirements and the optimal water management conditions for birdsfoot trefoil (Lotus corniculatus L.) when grown for seed production under humid temperate marine climatic conditions of western Oregon, USA. The experiment was conducted on a Woodburn silt loam soil (fine-silty, mixed, mesic Aquultic Argixeroll) near Corvallis. Four single-application treatments varying in water depletion percentage (30 and 60% of field capacity) and replenishment amount (50 and 100% of amount depleted) were applied in 1994 and 1995. A low-stress treatment (LS) that received two to three applications per week of the amount depleted since the last application and a non-irrigated control were also investigated in 1994, 1995, and 1996. Increasing amounts of applied water resulted in increased seasonal crop evapotranspiration (ETc) with plants grown under low-stress having the greatest ETc and non-irrigated control plants the least (r = 0.91). The fraction of available soil water used by nonirrigated plants was greatest and the LS treatment the least of all treatments. For non-irrigated conditions, the crop-water requirement ranged from 240 to 255 mm. Soil-water conditions favorable for high vegetative development were opposite of the renditions for optimal seed yield water-use efficiency. Unlike other forage legume seed crops, birdsfoot trefoil grown under these conditions required minimal or no supplemental irrigation to achieve maximal seed yield.

********************

Development of N-2-fixing nodules on the wetland legume Lotus uliginosus exposed to conditions of flooding.
James, E.K.; Sprent, J.I. 1999. New Phytologist 142:219-231.

Seeds of the wetland legume, Lotus uliginosus, were germinated and grown in vermiculite which was either continuously flooded or well-drained. Plants from both treatments were infected by Mesorhizobium loti strain DUS341 via a 'classical' root hair pathway, although some flooded plants appeared to be infected via enlarged epidermal cells. Subsequent to infection by M. loti, nodule meristems, which had developed within the root outer cortex, were penetrated by infection threads that released bacteria into the meristematic cells. The infection threads and infection droplets were immunogold labelled with monoclonal antibodies (MAC265 and MAC236) that recognize epitopes (at approx. 155/170 and 170/210 kDa, respectively) on a glycoprotein component of the matrix that surrounded the bacteria within the threads or droplets. Although labelling of infection threads or infection droplets with MAC236 was stronger than that with MAC265, both antibodies strongly labelled material occluding intercellular spaces in the cortices of developing nodules that had not yet expressed nitrogenase (as determined by a lack of signal after immunogold labelling with an antibody raised against nitrogenase component II). After 60 d, nitrogenase activity, shoot and root dry weights, and nodule fresh weight per plant did not differ between the treatments. After a further 30 d submergence, the flooded stems developed extensive aerenchyma and there was profuse development of (nodulated) adventitious roots. Nodules also formed at the junction of adventitious roots and the subtending stem and these were connected vascularly to a small stalk of tissue which gave rise to both a nodule and an adventitious root. The hooded nodules had prominent lenticels, and possible air pathways from the atmosphere to the nitrogen-fixing bacteroids are discussed.

********************

Effects of disturbance and rabbit grazing on seedling recruitment of six mesic grassland species.
Edwards, G.R.; Crawley, M.J. 1999. Seed Science Research 9:145-156.

Seeds of two grass (Arrhenatherum elatius and Festuca rubra), two herb (Plantago lanceolata and Rumex acetosa) and two legume (Lotus corniculatus and Trifolium repens) species were sown in summer 1995 at four densities (no seed, 1000, 10 000 and 50 000 seeds m(-2)) into an established rabbit-grazed grassland given factorial combinations of rabbit fencing (with and without fences) and soil disturbance (with and without cultivation). On plots where no seeds were sown, only the species with persistent seed banks (P. lanceolata, L. corniculatus and T: repens) showed enhanced seedling emergence in response to disturbance. In disturbed soil, seedling densities of all species increased with increasing density of sown seeds, the effects of which were still evident for plant cover 2 years after seed sowing. In undisturbed vegetation, A. elatius, F. rubra, P. lanceolata and R. acetosa showed increased seedling densities following seed sowing; but in each case, there was an upper asymptote to seedling recruitment, presumably due to microsite limitation. Rabbit grazing reduced seedling densities, with this reduction being more pronounced with disturbance than without. However, the effect of rabbit grazing did not persist for some species; seedling mortality of R. acetosa, P. lanceolata, L. corniculatus and T: repens was higher on plots without rabbit grazing, so that plant densities of these species in summer 1996 and plant cover in summer 1997 were greater on grazed plots. The results indicate interactions between soil disturbance, propagule availability and herbivory, rather than disturbance alone, will play an important role in controlling seedling recruitment and species habitat distributions in grasslands.

********************

Seed production of Lotus uliginosus cv. Sharnae in response to plant population density.
Arango, N.; Jacobs, B.C.; Blumenthal, M.J. 1998. In: Australian journal of experimental agriculture. v 38 p. 837-842.

********************

Forage legumes as living mulches for trees in agroforestry practices - preliminary results.
Alley, J.L.; Garrett, H.E.; McGraw, R.L.; Dwyer, J.P.; Blanche, C.A. 1998. Agroforestry Systems 44:281-291.

Successful establishment and growth of tree seedlings in an agroforestry practice is dependent on the control of competing herbaceous vegetation. Conventional weed control methods (i.e., chemical, mechanical, and physical suppression) are effective but can be costly in terms of time, damage to non-target vegetation, or increased soil erosion. Alternatively, some living mulches can exclude undesirable vegetation, protect the soil, compete minimally with associated trees, and supplement soil nitrogen. In this study, small and large white clover (Trifolium repens L.), red clover (T. pratense L.), kura clover (T. ambiguum Bieb.), strawberry clover (T. fragiferum L.), birdsfoot trefoil (Lotus corniculatus L.), hairy vetch and 'AU Early' hairy vetch (Vicia villosa Roth) were selected for evaluation as living mulches. These species were established in 9 m x 9 m replicated plots along with two controls [tall fescue (Festuca arundinacea Schreb.) and bare soil kept vegetation free using glyphosate]. The controls represent 'high competition' and 'no competition', respectively. Eastern black walnut (Juglans nigra L.), honeylocust (Gleditsia triacanthos L.), and hybrid pitch x loblolly pine (Pinus rigida L. x P. taeda L.) seedlings were planted in association with each living mulch. Tree seedling heights and diameters were measured during the first two years and forage performance evaluated. All seedlings grew better in the absence of competition. Tall fescue greatly reduced the growth of hardwood seedlings. Red clover and ladino clover showed the greatest promise as living mulches for use with the hardwood and pine seedlings, respectively.

********************

A grazing experiment, conducted for 55 days (from 4 March to 29 April) in the late summer/autumn of 1997, at Massey University, Palmerston North, New Zealand, compared the reproductive efficiency and wool growth of ewes grazing Lotus corniculatus (birdsfoot trefoil) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) dominant pasture (pasture). Half the ewes grazing each forage were given daily oral polyethylene glycol (PEG:molecular weight 3500) supplementation to inactivate the condensed tannins (CT) in lotus. A rotational grazing system with 200 mixed age ewes (54.2 +/- 0.88 kg/ewe; 50 ewes/treatment) was used. The effect of forage species and PEG supplementation upon voluntary feed intake (VFI), concentration of plasma metabolites, reproductive efficiency, wool production and wool characteristics was measured during two synchronized oestrous cycles. The ewes were restricted to maintenance feeding for the first 12 days of each oestrous cycle and then increased to ad libitum for the 6 days prior to and including ovulation. Lotus contained 17 g total CT/kg dry matter (DM) in the diet selected. There were only trace amounts of total CT in pasture. In vitro organic matter digestibility (OMD) was higher for lotus (0.82 v. 0.74) than for pasture, whilst lotus contained less nitrogen (N; 37.8 v. 44.5 g/kg OM). Mean ovulation rates (OR) for CT-acting and PEG sheep grazing pasture and lotus were respectively 1.33 v. 1.35 and 1.78 v. 1.56, with corresponding lambing percentages being 1.36 v. 1.36 and 1.70 v. 1.42. Fecundity (number of corpora lutea/ewe ovulating) was greater for ewes grazing lotus than pasture (P < 0.01), and tended to be greater for CT-acting than for PEG sheep grazing lotus(P = 0.06). In unsupplemented sheep, ewes grazing lotus had increased plasma concentrations of branched chain amino acids (BCAA; 57%) and essential amino acids (EAA; 52%) compared to ewes grazing pasture. In ewes grazing pasture, PEG administration had no effect on plasma concentrations of urea and free amino acids, VFI, reproductive efficiency and wool production. However, in sheep grazing lotus, plasma concentrations of urea were significantly lower and concentrations of most amino acids were significantly higher for CT-acting than for PEG supplemented ewes (CT not acting); there was no difference in VFI between these two groups. Compared to ewes grazing pasture, ewes grazing lotus had similar VFI but produced more wool with longer staples and thicker fibre diameter, with there being no effect of PEG supplementation. It was concluded that feeding lotus increased the efficiency of both reproduction and wool production without an increase in VFI, and that a possible cause was the action of CT in increasing plasma EAA and especially BCAA concentration.

********************

Germination and seedling growth at low temperature: comparisons of Lotus species and effects of selection and seed source in L. pedunculatus Cav.
Kelman, W.M.; Forrester, R.I. 1999. Australian Journal of Agricultural Research 50:969-975.

The association of seed size, type of life cycle (annual/perennial), and ploidy (diploid/tetraploid) with low temperature (5 degrees C), germination rate, and seedling growth was examined under controlled conditions in 9 Lotus species. Seeds harvested at 2 localities from 2 populations of L. pedunculatus, one selected for early flowering and the other unselected for flowering time, were included in the study to examine the influence of selection history and seed provenance on cold temperature germination rate and seedling growth. Seed size and ploidy level were not significant factors influencing germination rate of the Lotus species, but both seed size and life cycle had significant associations (P < 0.01) with seedling dry weight. Seed of the selected, early flowering population of L. pedunculatus germinated significantly faster than that of the unselected population (P < 0.01), and this difference was more pronounced in seed from the site where early flowering would confer advantages of better seed production and the potential for better persistence through seedling recruitment. A narrow-sense heritability estimate for the germination rate of L. pedunculatus was high at the 2 localities (0.84 +/- 0.17 and 0.65 +/- 0.16) and it was thus promising as a selection criterion for improved establishment. If interspecific hybridisation can be achieved between the annual and perennial species, a longer term prospect exists to utilise the high capacity of annual species to germinate and grow at low soil temperatures.

********************

Symbiotic effectiveness and ecological characterization of indigenous Rhizobium loti populations in Uruguay.
Baraibar, A.; Frioni, L.; Guedes, M.E.; Ljunggren, H. 1999. Pesquisa Agropecuaria Brasileira 34:1011-1017.

The objectives of this work were to describe the distribution, density and seasonal variation of the indigenous populations of Rhizobium loti in different Uruguayan soils and to determine the symbiotic effectiveness and stress tolerance factors of different isolates, both with the aim of obtaining selected strains to re-introduce as inoculants in Lotus pastures. R. loti was present in ten soils studied and their densities varied from year to year and within each soil. All the isolates nodulated Lotus corniculatus effectively. The nodules in Lotus pedunculatus and Lotus subbiflorus were small, red on the surface and ineffective in nitrogen fixation. The study of 50 isolates from the ten soils showed high variability in their symbiotic efficiency and tolerance to pH. The indigenous population was acid tolerant in culture medium (pH 4.5), 83% of them could grow at pH 4.5 in 3 days. This work showed that there was a great diversity between the strains of R. loti isolated from Uruguayan soils and supports the importance of selecting among them the most efficient and resistant strains to be included in the inoculants.

********************

Enhancement of botanical diversity of permanent grassland and impact on hay production in Environmentally Sensitive Areas in the UK.
Hopkins, A.; Pywell, R.F.; Peel, S.; Johnson, R.H.; Bowling, P.J. 1999. Grass and Forage Science 54:163-173.

Five methods for increasing the botanical diversity of permanent grassland, either by sowing site-specific species-rich grass/forb seed mixtures (strip-seeding; or over-sowing after sward disturbance by light harrowing, partial rotary cultivation or turf removal), or by introducing transplanted plug plants, were compared with a control treatment in replicated field experiments on six farm sites in Environmentally Sensitive Areas (ESAs) in England and Wales. Effects on herbage production under hay cutting in July and on botanical composition were recorded in the two subsequent years. Turf removal before sowing was the only treatment that significantly reduced herbage production; this treatment also had the greatest effect on increasing botanical diversity (to a mean of twenty-eight plant species per site compared with fifteen species for the control 2 years after sowing). The least successful establishment of sown species resulted from light harrowing before sowing; the rotary-cultivated and strip-seeded treatments increased species diversity, although by less than turf removal. Successful establishment of introduced species was greatest on sites having a low soil nutrient status. Species that established successfully from seed on most sites and treatments included the grasses Alopecurus pratensis, Cynosurus cristatus, Festuca rubra and Phleum pratense, and the forbs Achillea millefolium, Leucanthemum vulgare, Plantago lanceolata and Prunella vulgaris; in addition, Centaurea nigra, Hypochoeris radicata and Lotus corniculatus were also established by one or more methods on most sites, Lychnis flos-cuculi established successfully on mesotrophic sites, and Medicago lupulina on calcareous sites. Several species failed to establish at all or most sites where they were sown, e.g. Helianthemum nummularium, Pimpinella saxifraga and Rhinanthus minor. Most transplanted plug-plant species established successfully in the short term, but many failed to persist or their frequency in the sward remained low; exceptions included A. millefolium and P. lanceolata. The results are discussed in relation to the requirements for management to further the objectives of ESAs and agri-environmental schemes.

********************

Fusions between green fluorescent protein and beta-glucuronidase as sensitive and vital bifunctional reporters in plants [Erratum: Nov 1998, v. 38 (5), p. 917, 861-874.].
Quaedvlieg, N.E.M.; Schlaman, H.R.M.; Admiraal, P.C.; Wijting, S.E.; Stougaard, J.; Spaink, H.P. 1998. In: Plant molecular biology. 37:715-727.

By fusing the genes encoding green fluorescent protein (GFP) and beta-glucuronidase (GUS) we have created a set of bifunctional reporter constructs which are optimized for use in transient and stable expression studies in plants. This approach makes it possible to combine the advantage of GUS, its high sensitivity in histochemical staining, with the advantages of GFP as a vital marker. The fusion proteins were functional in transient expression studies in tobacco using either DNA bombardment or potato virus X as a vector, and in stably transformed Arabidopsis thaliana and Lotus japonicus plants. The results show that high level of expression does not interfere with efficient stable transformation in A. thaliana and L. japonicus. Using confocal laser scanning microscopy we show that the fusion constructs are very suitable for promoter expression studies in all organs of living plants, including root nodules. The use of these reporter constructs in the model legume L. japonicus offers exciting new possibilities for the study of the root nodulation process.

********************

Native vs. introduced bee flora: a palynological survey of honeys from Uruguay.
Daners, G.; Telleria, M.C. 1998. Journal of Apicultural Research 37:221-229.

A melissopalynological study was made to classify the botanical and geographical origin of 21 samples of commercial Uruguayan honeys. Sixty-six pollen types were found; 67% of the samples were unifloral. The taxa with the greatest frequencies (>15% of pollen in each sample) were Lotus corniculatus, Eucalyptus spp., Echium plantagineum, Scutia buxifolia and Baccharis spp. The taxa with highest occurrence (present in >85% of samples) were Eucalyptus spp., Trifolium pratense, L corniculatus, Schinus molle-type, Baccharis spp., Trifolium repens, Echium plantagineum, Eryngium spp., Scutia buxifolia, Salix humboldtiana and Poaceae. Forty-eight percent of the pollen taxa were endemic to the Americas; the majority of the other taxa were from Europe. The Uruguayan honeys we analysed typically contained pollen from the native Schinus molle type, Baccharis spp., Eryngium spp., Scutia buxifolia and Salix humboldtiana, together with pollen from the introduced Eucalyptus spp., L. corniculatus, T. pratense, T. repens and Echium plantagineum.

********************

Inheritance and expression of transgenes in T-2 and T-3 generations of Lotus corniculatus transformed using Agrobacterium tumefaciens.
Webb, K.J.; Humphreys, M.O.; Skot, L.; Gibbs, M.; Gatehouse, J. 1999. Euphytica 108:169-179.

The inheritance and expression of the reporter gene uidA, encoding beta-glucuronidase (GUS), was previously analysed in the T-1 generation of 25 independent transformed lines of Lotus corniculatus cv. Leo. In the work reported here, GUS activity in various tissues of seven of these lines was tested in the T-2 generation. Four representative lines were chosen for more detailed study in the T-3 generation. Lines 25 and 38 had multiple, independently segregating transgene inserts; lines 24 and 39 appeared to transmit one segregating transgene insert to their T-1 progeny, although transgene expression was low and was detected in fewer seedlings than expected in line 39. The uidA gene was inherited and expressed in seedlings of T-1, T-2 and T-3 generations of all four lines. In all lines, transgene expression varied between tissues, with more embryos than seedlings having detectable GUS activity. Studies in the T-2 generation showed that use of transgenic plants as female or male parents altered the frequency of expression of the transgene in progeny. By contrast, in the T-3 generation the use of transgenic plants as female or male parents did not effect either frequency of transmission, or expression of the transgene, in any of the four lines. Transgene inheritance was also similar among individual pods within flower heads and between individual flower heads.

********************

Shrub seedling recruitment in unburned Californian coastal sage scrub and adjacent grassland.
DeSimone, S.A.; Zedler, P.H. 1999. Ecology 80:2018-2032.

Shrub species of southern Californian coastal sage scrub recruit seedlings immediately after fire but also recruit in unburned coastal sage scrub stands and annual grasslands. We examined the influence of natural disturbances other than fire on shrub seedling establishment, especially the role of small-scale disturbance. Our goals were to determine: (1) whether seedling recruitment is associated with gaps in grassland, scrub, and grassland-scrub ecotones; (2) the identity of gap-creating agents; (3) the influences of biotic (vertebrates and ants) and abiotic (late spring moisture) disturbances on seedling establishment; and (4) whether disturbance effects vary spatially, both among and within (gap vs, nongap microsites) the three zones. We censused natural seedlings and vegetation gaps monthly in belt transects for two growing seasons and also measured seed banks at three 16-yr-old sites of adjacent grassland and coastal sage scrub. We initiated factorial experiments at one site to determine effects of animals, gaps, and late spring moisture on seed and seedling numbers. Gap-creating agents varied among the three zones, but seedlings were associated with gaps in each. Animals, especially small mammals, were important in creation and maintenance of gaps. Animal effects varied among but not within zones. Small mammals positively affected seedling recruitment in the grassland (germination on pocket gopher mounds) and negatively affected seed numbers of species with larger and multiple-seeded propagules in the ecotone and scrub; they created and/or maintained gaps in all three zones. Late spring moisture did not play an important role in shrub seedling recruitment in any zone. Because coastal sage shrub seedlings lose transpiring surfaces during drought, they may be less vulnerable than evergreen mediterranean shrubland species to the variability in both annual and seasonal extent of rainfall that is typical of mediterranean climates.

********************

Seed-to-seed allelopathic effects between two invaders of burned Pampa Grasslands.
Laterra, P.; Bazzalo, M.E. 1999. Weed Research 39:297-308.

The establishment of Lotus tenuis can interfere with colonization by Carduus acanthoides during the early post-burn recovery of Flooding Pampa grasslands. The purpose of this research was to determine the potential role of L. tenuis seeds as a source of allelopathic compounds involved in that interaction. Imbibed seeds of L. tenuis and aqueous leachates from them were bioassayed for their ability to inhibit germination and seedling growth of C. acanthoides, both on sterilized filter paper and on pasteurized soil as substrata. Germination and/or emergence of C, acanthoides were inhibited and root length was reduced on filter paper or soil, by both the presence of L, tenuis seeds and their leachate, at densities of L. tenuis near the maximum values observed in the field. Germination and seedling growth of C, acanthoides were less affected by the presence of L. tenuis seeds than by the addition of their leachate, and the presence of L. tenuis seeds or their leachate showed stronger effects on emergence of C, acanthoides from soil than on its germination on filter paper. Methods applied for leachate sterilization, ultrafiltration or autoclaving did not modify C, acanthoides responses. Neither the germination rate nor the root length of C, acanthoides seedlings were affected by solutions of polyethylene glycol with similar osmolarity to the leachates, We conclude that the release of inhibitory substances on to filter paper and into pot soil from imbibed L. tenuis seeds would be the mechanism responsible for the observed effects.

********************

Polyphenols and agriculture: beneficial effects of proanthocyanidins in forages.
Aerts, R.J.; Barry, T.N.; McNabb, W.C. 1999. Agriculture Ecosystems & Environment 75:1-12.

Proanthocyanidins (PA), also known as condensed tannins, belong to the oldest of plant secondary metabolites. These compounds are widespread in woody plants, but are also found in certain forages. Proanthocyanidins can exert effects in organisms because of their ability to complex with proteins. Forages containing moderate concentrations of PA (2-4% DM) can exert beneficial effects on protein metabolism in sheep, slowing degradation of dietary protein to ammonia by rumen micro-organisms and increasing protein outflow from the rumen, thus increasing absorption of amino acids in the small intestine of the animal. This was shown to result in increases in lactation, wool growth and liveweight gain, without changing voluntary feed intake. Dietary PA can also contribute to improved animal health by reducing the detrimental effects of internal parasites in sheep and the risk of bloat in cattle. In contrast, high dietary PA concentrations (6-12% DM) depress voluntary feed intake, digestive efficiency and animal productivity. Temperate forages containing PA, such as Lotus corniculatus and L. pedunculatus, will not persist in intensive grazing systems if continuously grazed (i,e. set stocked), especially in mixtures with perennial ryegrass and white clover and need to be grown as pure species and rotationally grazed. Nevertheless, inputs of these 'special purpose 'forages can increase sustainability and productivity in intensive grazing systems through increasing the efficiency of animal production, reducing urinary nitrogen (N) excretion and reducing chemical inputs as anthelmintics and as detergents used to control rumen bloat in cattle. Proanthocyanidins are derived from the flavonoid biosynthesis pathway, and knowledge is rapidly increasing about the molecular control of PA biosynthesis, These recent investigations may ultimately enable the expression by genetic engineering of increased levels of PA in the leaves of agriculturally important forage plants such as white clover and perennial rye grass, which will withstand continuous defoliation under grazing and currently contain only trace amounts of PA. This could potentially lead to the widespread use of PA in temperate grazing systems. Further consideration, should now be given to long-term adaptations in the animal, and to ecological effects on the soil ecosystem by PA and their degradation products excreted in animal faeces. More information is required in particular on the effects of PA on soil nitrification, ammonia volatilisation from soil, and nitrogen levels in the groundwater.

********************

Effect of competition on the responses of grasses and legumes to elevated atmospheric CO₂ along a nitrogen gradient: differences between isolated plants, monocultures and multi-species mixtures.
Navas, M.L.; Garnier, E.; Austin, M.P.; Gifford, R.M. 1999. New Phytologist 143:323-331.

The responses to CO₂ of perennial grasses (Danthonia richardsonii and Phalaris aquatica) and legumes (Lotus pedunculatus and Trifolium repens) were compared under controlled conditions for isolated plants, monoculture stands and mixed-species stands along a N gradient to test whether: plant-plant interactions between species in mixed stands changed with concentration of CO₂; responses to CO₂ of species in mixtures could be related to their responses as single stands; responses of mixtures to CO₂ could be related to the responses of individual species to CO₂ and to competition. Plants were grown for 60 d in sand, using nutrient solutions (six nitrate concentrations from 0.25 to 16 mM NO₃), at ambient (c. 357 mu l l(^-1)) or elevated CO₂ (c. 712 mu l l(^-1)). Species dominance in the mixtures depended more on the range of N than of CO₂ concentration provided: T. repens and L. pedunculatus dominated at low concentrations of N; L. pedunculatus and P. aquatica performed better at high concentrations. Responses of species in mixtures to CO₂ were related to their responses in monocultures but not to those of isolated plants. Species biomass proportions in mixtures under ambient CO₂ determined the outcome of mixture responses to CO₂ more than of individual species responses to CO₂. These results emphasize the influence of plant-plant interactions on community responses to CO₂, since mixture behaviour under elevated CO₂ could not be scaled-up from responses by isolated plants in this experiment.

********************

Productivity, botanical composition, and nutritive value of swards including forage chicory.
Belesky, D.P.; Fedders, J.M.; Turner, K.E.; Ruckle, J.H. 1999.Agronomy Journal 91:450-456.

Pure stands of 'Grasslands Puna' chicory (Cichorium intybus L.) are productive and responsive to N fertilization in the eastern USA. We conducted a field experiment for 3 yr to investigate productivity and nutritive value of swards including chicory, orchardgrass (Dactylis glomerata L.), and birdsfoot trefoil (Lotus corniculatus L,) as a function of clipping frequency (3- and 6-wk intervals). Each treatment was replicated three times on an upland site of Dekalb series soil (loamy-skeletal, mixed, subactive, mesic Typic Dystrochrept). Modest rates of N, P, and K were applied annually. Herbage mass, botanical composition, in vitro organic matter disappearance (IVOMD), and crude protein (CP) were determined. Cumulative herbage yield was not influenced by initial sward composition with chicory, chicory-orchardgrass, and chicory-orchardgrass-trefoil averaging 6.8 Mg ha(^-1) during a growing season. Clipping frequency influenced yield with canopies clipped at 6-wk intervals producing 26% more herbage than those clipped at 3-wk intervals. Growth rates of canopies clipped at 6-wk intervals averaged 51 kg ha(^-1) d(^-1) early in the growing season, suggesting that swards including chicory would be responsive to nutrient inputs and where rapid herbage regrowth and nutrient use by the growing crop are needed. Chicory declined in swards with time, regardless of initial sward composition or clipping frequency, Fluctuations in IVOMD and CP were related to changes in sward composition arising from the interaction of time and clipping frequency, Including orchardgrass and trefoil retarded invasion of less desirable species and so provided a means to control overall sward productivity and herbage composition.

********************

Sodium sulphite effects on recovery and composition of detergent fibre and lignin from forage legumes varying in levels of proanthocyanidins.
Krueger, C.G.; Albrecht, K.A.; Reed, J.D.; Bures, E.J.; Owens, V.N. 1999. Journal of the Science of Food and Agriculture 79:1351-1356.

Alfalfa (Medicago sativa L), red clover (Trifolium pratense L), birdsfoot trefoil (Lotus corniculatus L), sainfoin (Onobrychis viciifolia Scop), crownvetch (Coronilla varia L), cicer milkvetch (Astragrlus cicer L), sericea lespedeza (Lespedeza cuneata (Dum-Cours) G Don) and kura clover (Trifolium ambiguum M Bieb) were subjected to sequential detergent fibre analysis to investigate the effects that the addition of sodium sulphite to neutral detergent has on the recovery and composition of fibre and lignin from forage legumes that vary in levels of proanthocyanidin (PA). Soluble, insoluble and neutral detergent insoluble PA (NDIPA) concentrations were highest in sericea, moderate in crownvetch, sainfoin and birdsfoot trefoil and absent in alfalfa, cicer milkvetch, red clover and kura clover. Addition of sodium sulphite reduced levels of neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), neutral detergent insoluble nitrogen (NDIN) and acid detergent insoluble nitrogen (ADIN) recovered from most forages tested. The addition of sodium sulphite effectively eliminated NDIPA from NDF. The difference between fibre fractions prepared without and with the addition of sodium sulphite during the neutral detergent procedure was related to PA concentration. Neutral detergent fibre difference was positively correlated with soluble PA (r=0.730, p=0.0001), insoluble PA (r=0.905, p=0.0001) and NDIPA (r=0.913, p=0.0001). Acid detergent fibre difference was positively correlated with soluble PA (r =0.796, p =0.0001), insoluble PA (r = 0.976, p = 0.0001) and NDIPA (r = 0.974, p = 0.0001). Acid detergent lignin difference was positively correlated with soluble PA (r=0.846, p=0.0001), insoluble PA (r=0.992, p=0.0001) and NDIPA (r = 0.972, p = 0.0001). Neutral detergent insoluble nitrogen difference was positively correlated with soluble PA (r = 0.475, p = 0.0255), insoluble PA (r =0.579, p = 0.0047) and NDIPA (r =0.570, P =0.0056). Acid detergent insoluble nitrogen difference was positively correlated with soluble PA (r=0.798, p =0.0001), insoluble PA (r = 0.969, P = 0.0001) and NDIPA (r = 0.979, p = 0.0001). Sodium sulphite has large effects on fibre values of PA-containing species. Our results suggest that the difference between fibre fractions prepared with and without the addition of sulphite to neutral detergent may be used to determine the effects of PA on protein solubility in detergents.

********************

Responses of Lotus corniculatus to environmental change. 2. Effect of elevated CO₂, temperature and drought on tissue digestion in relation to condensed tannin and carbohydrate accumulation.
Carter, E.B.; Theodorou, M.K.; Morris, P. 1999. Journal of the Science of Food and Agriculture 79:1431-1440.

Clonal plants of three genotypes of Lotus corniculatus (cv Lee) were grown in eight controlled environments under combinations of two temperature regimes, two CO₂ concentrations and two watering regimes. Condensed tannins (proanthocyanidins), in-vitro digestibility, initial rates of gas evolution as an indicator of the initial rates of fermentation of the substrate), volatile fatty acid evolution, and non-structural carbohydrate (NSC) levels were determined in leaves, stems and roots at full flowering. Under control conditions (average midsummer conditions in the United Kingdom) the total condensed tannin content of leaves varied six-fold between genotypes but condensed tannin contents in stems and roots were similar. Condensed tannin levels were significantly increased in leaves and stems of all three genotypes by doubling the CO₂ concentration while raising the temperature towards the optimum for growth significantly reduced condensed tannin levels. Drought stress significantly reduced condensed tannin levels in leaves and, particularly, in roots. Nutritive value was inversely related to condensed tannin levels in leaves and a negative relationship was observed between condensed tannin concentrations of more than 25-30 g kg(^-1) dry matter and the initial rates of gas evolution when subjected to in-vitro fermentation with rumen micro-organisms. In leaves, digestibility was significantly increased by drought and by increasing temperature but reduced by high CO₂. In stems, digestibility was significantly increased by drought, but not significantly affected by increasing temperature, or by high CO₂ alone. In roots, digestibility was significantly increased by drought, and decreased by increasing temperature or CO₂. Increasing the growth temperature towards optimum growth reduced the content of NSC in all tissues with the greatest changes occurring in root tissue. Doubling the CO₂ concentration increased NSC levels in leaves and stems with starch content more than doubled under high CO₂ while, in roots, increased levels were only observed in combination with drought stress. There was a linear correlation between condensed tannin concentration and total NSC that was positive for leaves, neutral for stems and negative for roots. The relationship between carbohydrate levels and rates of gas production was negative for leaves and positive for stem and roots.

********************

Lotus japonicus nodulates and fixes nitrogen with the broad host range Rhizobium sp NGR234.
Hussain, AKMA.; Jiang, Q.Y.; Broughton, W.J.; Gresshoff, P.M. 1999. Plant and Cell Physiology 40:894-899.

Lotus japonicus possesses major advantages as a model legume for the study of plant-microbe interactions. The relative absence of genetic information on its normal microbial partner (i.e., Mesophizobium loti) could limit its utility in research. Here we show for the first time that the broad host range Rhizobium strain NGR234 nodulates and fixes nitrogen in symbiosis with Lotus japonicus ecotypes "Gifu" and "Funakura". We demonstrate that bacterial mutants deficient in nodulation or nitrogen fixation possess the expected phenotype with L. japonicus. Nodulation of L. japonicus was sensitive to nitrate. Vermiculite was an efficient synthetic growth substrate, allowing axenic growth in Magenta jars. The genetic analysis of the Lotus japonicus-Mesorhizobium interaction should be accelerated through the use of this well-defined microsymbiont.

********************

The final step of pantothenate biosynthesis in higher plants: cloning and characterization of pantothenate synthetase from Lotus japonicus and Oryza sativum (rice).
Genschel, U.; Powell, C.A.; Abell, C.; Smith, A.G. 1999. Biochemical Journal 341:669-678.

We have isolated a Lotus japonicus cDNA for pantothenate (vitamin B-5) synthetase (PS) by functional complementation of an Escherichia coli pan C mutant (AT1371), A rice (Oryza sativum) expressed sequence tag, identified by sequence similarity to PS, was also able to complement the E, coli auxotroph, as was an open reading frame from Saccharomyces cerevisiae (baker's yeast). The Lotus and rice cDNAs encode proteins of approx. 34 kDa, which are 65 % similar at the amino acid level and do not appear to encode N-terminal extensions by comparison with PS sequences from other organisms. Furthermore, analysis of genomic sequence flanking the coding sequence for PS in Lotus suggests the original cDNA is full-length. The Lotus and rice PSs are therefore likely to be cytosolic, Southern analysis of Lotus genomic DNA indicates that there is a single gene for PS. Recombinant PS from Lotus, overexpressed in E, coli AT1371, is a dimer, The enzyme requires D-pantoate, beta-alanine and ATP for activity and has a higher affinity for pantoate (K-m 45 mu M) than for beta-alanine (K-m 990 mu M). Uncompetitive substrate inhibition becomes significant at pantoate concentrations above 1 mM. The enzyme displays optimal activity at about 0.5 mM pantoate (k(cat) 0.63 s(-1)) and at pH 7.8. Neither oxopantoate nor pantoyl-lactone can replace pantoate as substrate. Antibodies raised against recombinant PS detected a band of 34 kDa in Western blots of Lotus proteins from both roots and leaves, The implications of these findings for pantothenate biosynthesis in plants are discussed.

********************

Proline is involved in water stress responses of Lotus corniculatus nitrogen fixing and nitrate fed plants.
Borsani, O.; Diaz, P.; Monza, J. 1999. Journal of Plant Physiology 155:269-273.

Water stress induced proline accumulation in Lotus corniculatus regardless of the nitrogen source provided to plants, although this accumulation was higher in nitrogen fixing plants. Enzymes related to synthesis and oxidation of proline were analysed. Fd-GOGAT activity and Fd-GOGAT protein content increased in response to water stress in contrast to PDH activity, which decreased under such condition. However, rehydration for 6 h induced an increment in PDH activity. The differential effect of water deficit on enzymes involved in the proline pathway in L. corniculatus plants growing under different nitrogen regimes is discussed. The possible role of nitrate as an osmoprotectant in the place of proline is also considered.

********************

Genetic nomenclature guidelines for the model legume Lotus japonicus.
Stougaard, J.; Szczyglowski, K.; de Bruijn, F.J.; Parniske, M. 1999. Trends in Plant Science 4:300-301.

********************

Birdsfoot trefoil seed production: I. Crop-water requirements and response to irrigation.
Garcia-Diaz, C.A.; Steiner, J.J. 1999. Crop Science 39:775-783.

********************

Development of N-2-fixing nodules on the wetland legume Lotus uliginosus exposed to conditions of flooding.
James, E.K.; Sprent, J.I. 1999. New Phytologist 142:219-231.

********************

Effects of disturbance and rabbit grazing on seedling recruitment of six mesic grassland species.
Edwards, G.R.; Crawley, M.J. 1999. Seed Science Research 9:145-156.

********************

Native vs. introduced bee flora: a palynological survey of honeys from Uruguay.
Daners, G.; Telleria, M.C. 1998. Journal of Apicultural Research 37:221-229.

********************

Shrub seedling recruitment in unburned Californian coastal sage scrub and adjacent grassland.
DeSimone, S.A.; Zedler, P.H. 1999. Ecology 80:2018-2032.

********************

Seed-to-seed allelopathic effects between two invaders of burned Pampa Grasslands.
Laterra, P.; Bazzalo, M.E. 1999. Weed Research 39:297-308.

********************

Polyphenols and agriculture: beneficial effects of proanthocyanidins in forages.
Aerts, R.J.; Barry, T.N.; McNabb, W.C. 1999. Agriculture Ecosystems & Environment 75:1-12.

********************

The responses to CO₂ of perennial grasses (Danthonia richardsonii and Phalaris aquatica) and legumes (Lotus pedunculatus and Trifolium repens) were compared under controlled conditions for isolated plants, monoculture stands and mixed-species stands along a N gradient to test whether: plant-plant interactions between species in mixed stands changed with concentration of CO₂; responses to CO₂ of species in mixtures could be related to their responses as single stands; responses of mixtures to CO2 could be related to the responses of individual species to CO₂ and to competition. Plants were grown for 60 d in sand, using nutrient solutions (six nitrate concentrations from 0.25 to 16 mM NO₃), at ambient (c. 357 mu l l(^-1)) or elevated CO₂ (c. 712 mu l l(^-1)). Species dominance in the mixtures depended more on the range of N than of CO₂ concentration provided: T. repens and L. pedunculatus dominated at low concentrations of N; L. pedunculatus and P. aquatica performed better at high concentrations. Responses of species in mixtures to CO₂ were related to their responses in monocultures but not to those of isolated plants. Species biomass proportions in mixtures under ambient CO₂ determined the outcome of mixture responses to CO₂ more than of individual species responses to CO₂. These results emphasize the influence of plant-plant interactions on community responses to CO₂, since mixture behaviour under elevated CO₂ could not be scaled-up from responses by isolated plants in this experiment.

********************

Productivity, botanical composition, and nutritive value of swards including forage chicory.
Belesky, D.P.; Fedders, J.M.; Turner, K.E.; Ruckle, J.H. 1999.Agronomy Journal 91:450-456.

Pure stands of 'Grasslands Puna' chicory (Cichorium intybus L.) are productive and responsive to N fertilization in the eastern USA. We conducted a field experiment for 3 yr to investigate productivity and nutritive value of swards including chicory, orchardgrass (Dactylis glomerata L.), and birdsfoot trefoil (Lotus corniculatus L,) as a function of clipping frequency (3- and 6-wk intervals). Each treatment was replicated three times on an upland site of Dekalb series soil (loamy-skeletal, mixed, subactive, mesic Typic Dystrochrept). Modest rates of N, P, and K were applied annually. Herbage mass, botanical composition, in vitro organic matter disappearance (IVOMD), and crude protein (CP) were determined. Cumulative herbage yield was not influenced by initial sward composition with chicory, chicory-orchardgrass, and chicory-orchardgrass-trefoil averaging 6.8 Mg ha(-1) during a growing season. Clipping frequency influenced yield with canopies clipped at 6-wk intervals producing 26% more herbage than those clipped at 3-wk intervals. Growth rates of canopies clipped at 6-wk intervals averaged 51 kg ha(-1) d(-1) early in the growing season, suggesting that swards including chicory would be responsive to nutrient inputs and where rapid herbage regrowth and nutrient use by the growing crop are needed. Chicory declined in swards with time, regardless of initial sward composition or clipping frequency, Fluctuations in IVOMD and CP were related to changes in sward composition arising from the interaction of time and clipping frequency. Including orchardgrass and trefoil retarded invasion of less desirable species and so provided a means to control overall sward productivity and herbage composition.

********************

We have isolated a Lotus japonicus cDNA for pantothenate (vitamin B-5) synthetase (PS) by functional complementation of an Escherichia coli pan C mutant (AT1371), A rice (Oryza sativum) expressed sequence tag, identified by sequence similarity to PS, was also able to complement the E, coli auxotroph, as was an open reading frame from Saccharomyces cerevisiae (baker's yeast). The Lotus and rice cDNAs encode proteins of approx. 34 kDa, which are 65 % similar at the amino acid level and do not appear to encode N-terminal extensions by comparison with PS sequences from other organisms. Furthermore, analysis of genomic sequence flanking the coding sequence for PS in Lotus suggests the original cDNA is full-length. The Lotus and rice PSs are therefore likely to be cytosolic, Southern analysis of Lotus genomic DNA indicates that there is a single gene for PS. Recombinant PS from Lotus, overexpressed in E, coli AT1371, is a dimer, The enzyme requires D-pantoate, beta-alanine and ATP for activity and has a higher affinity for pantoate (K^-m 45 mu M) than for beta-alanine (K^-m 990 mu M). Uncompetitive substrate inhibition becomes significant at pantoate concentrations above 1 mM. The enzyme displays optimal activity at about 0.5 mM pantoate (k(cat) 0.63 s(^-1)) and at pH 7.8. Neither oxopantoate nor pantoyl-lactone can replace pantoate as substrate. Antibodies raised against recombinant PS detected a band of 34 kDa in Western blots of Lotus proteins from both roots and leaves, The implications of these findings for pantothenate biosynthesis in plants are discussed.

********************

Proline is involved in water stress responses of Lotus corniculatus nitrogen fixing and nitrate fed plants.
Borsani, O.; Diaz, P.; Monza, J. 1999. Journal of Plant Physiology 155:269-273.

********************

Genetic nomenclature guidelines for the model legume Lotus japonicus.
Stougaard, J.; Szczyglowski, K.; de Bruijn, F.J.; Parniske, M. 1999. Trends in Plant Science 4:300-301.

********************

A Nod factor-binding lectin is a member of a distinct class of apyrases that may be unique to the legumes.
Roberts, N.J.; Brigham, J.; Wu, B.; Murphy, J.B.; Volpin, H.; Phillips, D.A.; Etzler, M.E. 1999. Molecular and General Genetics Vol. 262:261-267.

Recent studies from our laboratory have found that a root lectin from the legume Dolichos biflorus is present on the root surface, binds rhizobial Nod factor and has apyrase activity. To assess the broader significance of this lectin/nucleotide phosphohydrolase (Db-LNP), we have cloned a second related cDNA (Db-apyrase-2) from D. biflorus, as well as related cDNAs from the legumes Lotus japonicus and Medicago sativa, and from Arabidopsis thaliana, a non-legume. The deduced amino acid sequences of these apyrases were aligned with one another and with the sequences of other apyrases from plants, animals, yeast and protozoa. Phylogenetic analysis shows that Db-LNP has closely related orthologs only in other legumes, while Db-apyrase-2 is more closely related to apyrase sequences from non-leguminous plants. We also show that the orthologs of Db-LNP from M. sativa and Pisum sativum have carbohydrate binding activity. The results suggest that legume LNPs may represent a special class of apyrases that arose by gene duplication and subsequent specialization.

********************

Does root glutamine synthetase control plant biomass production in Lotus japonicus L.?
Limami, A.; Phillipson, B.; Ameziane, R.; Pernollet, N.; Jiang, Q.J.; Poy, R.; Deleens, E.; Chaumont-Bonnet, M.; Gresshoff, P.M.; Hirel, B. 1999. Planta Vol. 209: 495-502.

To investigate the contribution of root cytosolic glutamine synthetase (GS) activity in plant biomass production, two different approaches were conducted using the model legume Lotus japonicus. In the first series of experiments, it was found that overexpressing GS activity in roots of transgenic plants leads to a decrease in plant biomass production. Using N^-15 labelling it was shown that this decrease is likely to be due to a lower nitrate uptake accompanied by a redistribution to the shoots of the newly absorbed nitrogen which cannot be reduced due to the lack of nitrate reductase activity in this organ. In the second series of experiments, the relationship between plant growth and root GS activity was analysed using a series of recombinant inbred lines issued from the crossing of two different Lotus ecotypes, Gifu and Funakura. It was confirmed that a negative relationship exists between root GS expression and plant biomass production in both the two parental lines and their progeny. Statistical analysis allowed it to be estimated that at least 13% of plant growth variation can be accounted for by variation in GS activity.

********************

A strong constitutive positive element is essential for the ammonium-regulated expression of a soybean gene encoding cytosolic glutamine synthetase.
Terce-Laforgue, T.; Carrayol, E.; Cren, M.; Desbrosses, G.; Hecht, V.; Hirel, B. 1999.Plant molecular biology. v.39:551-564.

In order to identify important promoter elements controlling the ammonium-regulated expression of the soybean gene GS15 encoding cytosolic glutamine synthetase, a series of 5' promoter deletions were fused to the GUS reporter gene. To allow the detection of positive and negative regulatory elements, a series of 3' deletions were fused to a -90 CaMV 35S promoter fragment placed upstream of the GUS gene. Both types of construct were introduced into Lotus corniculatus plants and soybean roots via Agrobacterium rhizogenes-mediated transformation. Both spectrophotometric enzymatic analysis and histochemical localization of GUS activity in roots, root nodules and shoots of transgenic plants revealed that a strong constitutive positive element (SCPE) of 400 bp, located in the promoter distal region is indispensable for the ammonium-regulated expression of GS15. Interestingly, this SCPE was able to direct constitutive expression in both a legume and non-legume background to a level similar to that driven by the CaMV 35S full-length promoter. In addition, results showed that separate proximal elements, located in the first 727 bp relative to the transcription start site, are essential for root- and root nodule-specific expression. This proximal region contains an AAAGAT and two TATTTAT consensus sequences characteristic of nodulin or nodule-enhanced gene promoters. A putative silencer region containing the same TATTTAT consensus sequence was identified between the SCPE and the organ-specific elements. The presence of positive, negative and organ-specific elements together with the three TATTTAT consensus sequences within the promoter strongly suggest that these multiple promoter fragments act in a cooperative manner, depending on the spatial conformation of the DNA for trans-acting factor accessibility.

********************

Effects of trefoil cover crops and earthworm inoculation on maize crop and soil organisms in Reunion Island.
Boyer, J.; Michellon, R.; Chabanne, A.; Reversat, G.; Tibere, R. 1999. Biology and fertility of soils. 28:364-370.

Traditional tree fallows have been abandoned on the western coast of the Reunion Island because of the increasing need for cultivated land. Soil fertility is no longer restored and crop yields have decreased drastically. The leguminous plant, Lotus uliginosus (trefoil), used as a cover crop, has made possible the control of erosion, the restoration of soil macrofauna, especially earthworms, and the increase in crop yields. When trefoil was associated with earthworms (Amynthas corticis), the densities of maize, the yields of maize stalk and dry matter, the yield of trefoil fodder dry matter, and the biomass and respiratory activity of soil microflora were considerably increased. The combined effects of their association led to a significant decrease in populations of the plant-parasitic nematode, Pratylenchus vulnus, in maize roots, and in the population of borers. Some soil chemical features were modified.

********************

A plant regulator controlling development of symbiotic root nodules.
Schauser, L.; Roussis, A.; Stiller, J.; Stougaard, J. 1999. Nature Vol. 402:191-195.

Symbiotic nitrogen-fixing root nodules on legumes are founded by root cortical cells that de-differentiate and restart cell division to establish nodule primordia. Bacterial microsymbionts invade these primordia through infection threads laid down by the plant and, after endocytosis, membrane-enclosed bacteroids occupy cells in the nitrogen-fixing tissue of functional nodules. The bacteria excrete lipochitin oligosaccharides(1,2), triggering a developmental process that is controlled by the plant and can be suppressed. Nodule inception initially relies on cell competence in a narrow infection zone located just behind the growing root tip. Older nodules then regulate the number of nodules on a root system by suppressing the development of nodule primordia(3). To identify the regulatory components that act early in nodule induction, ive characterized a transposon-tagged Lotus japonicus mutant, nin (for nodule inception), arrested at the stage of bacterial recognition. We show that rlin is required for the formation of infection threads and the initiation of primordia. NlN protein has regional similarity to transcription factors, and the predicted DNA-binding/dimerization domain identifies and typifies a consensus motif conserved in plant proteins with a function in nitrogen-controlled development.

********************

The hydraulic conductivity of excised roots (Lp(r)) of the legume Lotus japonicus (Regel) K. Larsen grown in mist (aeroponic) and sand cultures, was found to vary over a 5-fold range during a day/night cycle. This behaviour was seen when Lp(r) was measured in roots exuding, either under root pressure (osmotic driving force), or under an applied hydrostatic pressure of 0.4 MPa which produced a rate of water flow similar to that in a transpiring plant. A similar daily pattern of variation was seen in plants grown in natural daylight or in controlled-environment rooms, in plants transpiring at ambient rates or at greatly reduced rates, and in plants grown in either aeroponic or sand culture. When detached root systems were connected to a root pressure probe, a marked diurnal variation was seen in the root pressure generated. After excision, this circadian rhythm continued for some days. The hydraulic conductivity of the plasma membrane of individual root cells was measured during the diurnal cycle using a cell pressure probe. Measurements were made on the first four cell layers of the cortex, but no evidence of any diurnal fluctuation could be found. It was concluded that the conductance of membranes of endodermal and stelar cells may be responsible for the observed diurnal rhythm in root Lp(r). When mRNAs from roots were probed with cDNA from the Arabidopsis aquaporin AthPIP1a gene, an abundant transcript was found to vary in abundance diurnally under high-stringency conditions. The pattern of fluctuations resembled closely the diurnal pattern of variation in root Lp(r). The plasma membranes of root cells were found to contain an abundant hydrophobic protein with a molecular weight of about 31 kDa which cross-reacted strongly to an antibody raised against the evolutionarily conserved N-terminal amino acid sequence of AthPIP1a.

********************

Transcription of a maize cDNA in Lotus corniculatus is regulated by T-DNA methylation and transgene copy number.
Bellucci, M.; Alpini, A.; Paolocci, F.; Damiani, F.; Arcioni, S. 1999. Theoretical and applied genetics. v. 98:257-264.

Lotus corniculatus plants transformed with a maize cDNA (G1L) encoding a sulphur-rich gamma-zein were obtained by using two fusion genes: one with the CaMV 35S promoter, the other with the ribulose bisphosphate carboxylase small subunit (rbcS) promoter. The highest expression of G1L mRNA was found in plants transformed with G1L under the rbcS promoter. The steady state level of G1L mRNA in the leaves was generally directly correlated with the G1L copy number. However, due to a transcriptional block, no G1L mRNA was detected in some of the 35S-G1L multicopy transformants. Analyses with methylation-sensitive restriction enzymes revealed that the T-DNA of the silenced 35S-G1L transformants was methylated. T-DNA copy number, G1L silencing activity, and the state of methylation were strictly correlated in primary transformants. A cross between two 35S-G1L transformed plants, one (S) with the T-DNA methylated and the other (NS) without, showed that: (1) the methylated state of T-DNA passed through meiosis; and (2) when T-DNA copies from the two parents were combined in the progeny, the unmethylated T-DNA copies of parent NS became methylated at different levels and G1L mRNA production was dependent on the degree of methylation.

********************

Effects of disturbance and rabbit grazing on seedling recruitment of six mesic grassland species.
Edwards, G.R.; Crawley, M.J. 1999. Seed science research. v. 9:145-156.

********************

Inheritance and expression of transgenes in T2 and T3 generations of Lotus corniculatus transformed using Agrobacterium tumefaciens.
Webb, K.J.; Humphreys, M.O.; Skot, L.; Gibbs, M.; Gatehouse, J. 1999. Euphytica v. 108:169-179.

********************

Comparative performance of enterobacterial repetitive intragenic consensus-polymerase chain reaction and lipopolysaccharide electrophoresis for the identification of Bradyrhizobium sp. (Lotus) strains.
Santamaria, M.; Agius, F.; Monza, J.; Gutierrez-Navarro, A.M.; Corzo, J. 1999. FEMS microbiology ecology. v. 28:163-168.

********************

Influence of leaf chemistry of Lotus corniculatus (Fabaceae) on larval development of Polyommatus icarus (Lepidoptera, Lycaenidae): effects of elevated CO₂ and plant genotype.
Goverde, M.; Bazin, A.; Shykoff, J.A.; Erhardt, A. 1999. Functional Ecology Vol. 13:801-810.

1. Four Lotus corniculatus genotypes differing in cyanoglycoside and condensed tannin concentrations were grown in either low (350 ppm) or high (700 ppm) atmospheric CO₂ environments. Larval performance, consumption and conversion efficiency of Polyommatus icarus feeding on this plant material were measured. 2. Plants grown under elevated CO₂ contained less cyanoglycosides, more condensed tannins and more starch than control plants. However, water concentration, nitrogen and protein as well as nitrogen concentration in relation to carbon concentration did not differ between CO₂ treatments. 3. The four genotypes differed significantly in condensed tannins, cyanoglucoside, leaf water and leaf nitrogen but no genotype-CO₂ interaction was detected, except for total phenolics and condensed tannins in which two plant genotypes showed stronger increases under elevated CO₂ than the other two. 4. Larvae of P. icarus consumed more plant material and used and converted it more efficiently from plants grown at high atmospheric CO₂. 5. Larvae developed significantly faster and were significantly heavier when fed plant material grown under elevated CO₂. The observed difference in mass disappeared in the pupal and adult stages. However, lipid concentration of adults from the elevated CO₂ treatment was marginally significantly higher than of controls. 6. It is concluded that the higher carbohydrate concentration of L. corniculatus plants grown at elevated CO₂ renders leaves more suitable and better digestible to P. icarus. Furthermore, differences in allelochemicals might influence the palatability of L. corniculatus leaves for this specialist on Fabaceae.

********************

Dispersal, distribution, patch network and metapopulation dynamics of the dingy skipper butterfly (Erynnis tages).
Gutierrez, D.; Thomas, C.D.; Leon-Cortes, J.L. 1999. Oecologia Vol. 121: 506-517.

Two general approaches have usually been taken towards understanding the distributions and dynamics of localised species in heterogeneous landscapes, namely habitat characterisation and metapopulation dynamics. We show how habitat and metapopulation dynamics interact to generate a highly localised distribution of a butterfly, despite the extremely widespread nature of the butterfly's host plant. Egg placement, macro-habitat requirements and dispersal were studied for the butterfly Erynnis tages, in North Wales, where it shows a restricted distribution relative to that of its host plant, Lotus corniculatus. Females laid eggs disproportionately on large plants growing in hollows, with intermediate cover of bare ground and high cover of L. corniculatus. Ideal macro-habitat, studied at 100-m grid resolution, consisted of areas with high host plant densities, sheltered from wind, with light or no grazing or cutting. These specialised conditions are represented as localised patches in the landscape, and define the potential habitat network, within which metapopulation dynamics take place. Although there was a moderate (22%) level of exchange of individual E. tages among local populations, the total number of potential colonists in the whole system was low because source population sizes were small (less than or equal to 200 individuals at peak in any site in 1997 and 1998). Four unoccupied but apparently suitable 500-m grid squares were colonised between 1997 and 1998, and isolated habitat was less likely to be occupied. Overall, our study suggests that long-term regional persistence of E. rages is very likely to depend on metapopulation processes within the restricted patch network, rather than on the long-term survival of local populations.

********************

Flavonoids in seed and root exudates of Lotus pedunculatus and their biotransformation by Mesorhizobium loti.
Steele, H.L.; Werner, D.; Cooper, J.E. 1999. Physiologia Plantarum Vol. 107: 251-258.

Analysis of the flavonoid content of seed and root exudates of Lotus pedunculatus was undertaken using multiple coupled analytical techniques: capillary zone electrophoresis coupled to a UV spectral array detector (CZE-UV), high performance thin-layer chromatography with densitometry (HPTLC-UV) and gas chromatography with mass spectrometry (GC-MS). These procedures provided separation, identification and structural confirmation of the previously unidentified flavonoids in this plant's seed and root exudates and were particularly applicable to samples from a small seeded legume. Catechin, naringenin, kaempferol, quercetin aglycone and 3 different glycosides of quercetin were detected in seed exudate. Sterile root exudates contained catechin, naringenin and quercetin in addition to apigenin, kaempferol and other flavones and flavanones for which partial identifications were obtained. When sterile root exudate was incubated with, Mesorhizobium loti, changes in its flavonoid content mere detected. Analysis of bacterial cells after incubation revealed the presence of quercetin, kaempferol and one other flavone. The monocyclic aromatics protocatechuic acid and phloroglucinol were detected in both the incubated root exudate and its bacterial cells.

********************

Lectin binding studies of parotid salivary glycoproteins in Sjogren's Syndrome.
Carpenter, G.H.; Pankhurst, C.L.; Proctor, G.B. 1999. Vol. 20:2124-2132.

Human parotid salivas were collected from patients with secondary Sjogren's syndrome and controls without disease or with drug-induced xerostomia. Parotid glycoproteins were separated by gradient sodium dodecyl sulphate gel electrophoresis (SDS-PAGE), electroblotted onto nitrocellulose membrane and probed with biotinylated lectins of characterised sugar specificities. The binding patterns of lectins from Maclura pomifera (MPA) and Arachis hypogaea (PNA) indicated that many parotid glycoproteins have sialylated O-linked glycans and that sialylation is not affected by disease. Binding by lectins from Ricinus communis (RCA-1), Limax flavus (LFA), Lotus tetragonolobus (LTA) and Ulex europaeus (UEA-1) appeared unaltered in secondary Sjogren's syndrome, suggesting no obvious change in N-glycosylation of parotid glycoproteins. Variations in binding patterns of most lectins was attributable to subject-to-subject variations in recognised polymorphic proteins. Dolichos biflorus agglutinin (DBA) consistently showed increased binding to a 75 kDa (M-r) protein in salivas from patients with secondary Sjogren's syndrome. The binding protein was identified as lactoferrin but found not to contain N-acetylgalactosamine, the sugar to which DBA binds. Binding of DBA to lactoferrin was dependent upon its saturation with iron, modified SDS-PAGE under nonreducing conditions resolved iron-free and iron-saturated lactoferrins and demonstrated increased levels of the iron-saturated form in secondary Sjogren's syndrome. Lectin binding studies of purified lactoferrins from saliva, milk, and polymorphonuclear neutrophils suggested that raised levels of lactoferrin in saliva originate from salivary cells and not from inflammatory cells. These results suggest that DBA binding provides greater specificity as an indicator of salivary gland disease than measurement of lactoferrin levels alone.

********************

Current and elevated levels of UV-B radiation have few impacts on yields of perennial forage crops.
Papadopoulos, Y.A.; Gordon, R.J.; McRae, K.B.; Bush, R.S.; Belanger, G.; Butler, E.A.; Fillmore, SAE.; Morrison, M. 1999. Global Change Biology Vol. 5:847-856.

Two experiments assessed the effect of current and elevated levels of ultraviolet(B) (UV-B) radiation on forage crop production. The effect of current levels of UV-B radiation was assessed by comparing the growth of eight cultivars of four legume and four grass species for three growing seasons (1994-96) under simulated sward conditions in the field. An exclusion system using cellulose diacetate or polyester covers provided comparable growing conditions for the plants, except for the presence or absence of ambient UV-B radiation, respectively. The second experiment studied the effect of elevated levels of UV-B on eight cultivars of two legume and two grass species in the greenhouse under simulated sward conditions. Natural lighting with sufficient supplemental light was used to provide ideal growing conditions for a 16-h day length. Separate sets of UV lights were installed to provide UV-B levels at approximately the same intensity as would be found in mid summer, and 33% and 66% more than this value. A fourth treatment consisted of removing UV-B radiation by using a polyester filter. Plant production was measured in both experiments. In 1994, field herbage yields from all young grass and legume seedlings were not significantly affected by the exclusion of ambient UV-B radiation, with the exception of alfalfa. Intra-specific variations with alfalfa yields were found for reduced levels of UV-B radiation. In general, these trends persisted as stands matured during two post seeding years. In the second experiment, no significant differences were observed for all tested species with increasing levels of UV-B radiation, except with some alfalfa cultivars and one birdsfoot trefoil cultivar. Collectively, these results demonstrate that in the northern latitudes young and mature plants of the studied species are resistant to current and potentially higher levels of solar UV-B radiation, with the exception of some alfalfa cultivars. The yield of these cultivars increased under enhanced levels of UV-B radiation in the greenhouse and decreased when UV-B was excluded in the field.

********************

It has been shown that N-, P- and S-deficiencies result in major reductions of root hydraulic conductivity (Lp(r)) which may lead to lowered stomatal conductance. but the relationship between the two conductance changes is not understood. In a variety of species, Lp(r) decreases in the early stages of NO3-, H2PO42- and SO42- deprivation. These effects can be reversed in 4-24 h after the deficient nutrient is re-supplied. Diurnal fluctuations of root Lp(r) have also been found in some species, and an example of this is given for Lotus japonicus. In nutrient-sufficient wheat plants, root Lp(r) is extremely sensitive to brief treatments with HgCl2; these effects are completely reversible when Hg is removed. The low values of Lp, in N- or P-deprived roots of wheat are not affected by Hg treatments. The properties of plasma membrane (PM) vesicles from wheat roots are also affected by NO3--deprivation of the intact plants. The osmotic permeability of vesicles from N-deprived roots is much lower than that of roots adequately supplied with NO3- and is insensitive to Hg treatment. In roots of Lp(r) japonicus, gene transcripts are found which have a strong homology to those encoding the PIP1 and PIP2 aquaporins of Arabidopsis. There is a very marked diurnal cycle in the abundance of mRNAs of aquaporin gene homologues in roots of L. japonicus. The maxima and minima appear to anticipate the diurnal fluctuations in Lp(r) by 2-4 h. The temporal similarity between the cycles of the abundance of the mRNAs and root Lp(r) is most striking. The aquaporin encoded by AtPIP1 is known to have its water permeation blocked by Hg binding. The lack of Hg-sensitivity in roots and PMs from N-deprived roots provides circumstantial evidence that lowered root Lp(r) may be due to a decrease in either the activity of water channels or their density in the PM. It is concluded that roots are capable, by means completely unknown, of monitoring the nutrient content of the solution in the root apoplasm and of initiating responses that anticipate by hours or days any metabolic disturbances caused by nutrient deficiencies. It is the incoming nutrient supply that is registered as deficient, not the plant's nutrient status. At some point, close to the initiation of these responses, changes in water channel activity may be involved, but the manner in which monitoring of nutrient stress is transduced into an hydraulic response is also unknown.

********************

Legumes have been shown to increase production in cool-season grass pastures. However, they are included he relatively few acres of pasture. A split plot experiment with six replications was conducted to evaluate the impact of pasture renovation and grazing management on forage production and species composition of cool-season grass pastures. Grazing management main plots were grazed to leave low (2-4 in.), medium (4-6 in.), or high (6-8 in.) residue levels, Main plots were intensively grazed (50 000-70 000 lb of cows per acre) five or six times per grazing season by lactating Holstein cows, Subplot pasture renovation treatments were (i) an untreated check, or sprayed with glyphosate and interseeded with (ii) alfalfa (Medicago sativa L.) (iii) red clover (Trifolium pratense L.) and birdsfoot trefoil (Lotus corniculatus L.), or (iv) "graziers mix" (a mixture of legumes and grasses), Areas that were grazed to leave low residue level produced less forage mass (4.7 ton/acre) than areas grazed to medium (5.4 ton/acre) or high (5.5 ton/acre) residue levels. When averaged across years and grazing management treatments, renovated areas produced 1.8 ton/acre (46%) more forage than the control, Of interseeded species, alfalfa, red clover, and orchardgrass persisted through the study (more theta 25% of the dry matter in st least one of the pasture renovation treatments). By June 1998, thistle (Carduus and Cirsium spp.) was present in all treatments. Fewer thistle was present in areas that were grazed to leave low residue (10 sq yd) than high residue (18 sq yd) and in renovated areas (9 sq yd) than the control (22 sq yd). The additional forage produced as a result of pasture renovation cost from $8.07/ton to $12.81/ton. This study indicates that pasture renovation can be a valuable tool for increasing forage production in cool-season grass pastures.

********************

Evaluation of the population dynamics of the forage legume Lotus corniculatus using matrix population models.
Emery, K.M.; Beuselinck, P.; English, J.T. 1999. New Phytologist Vol. 144:549-560.

The population dynamics of perennial crop plants are influenced by numerous factors, including management practices. Conditions in the field vary from year to year, and matrix population models are useful for evaluating population behaviour in relation to environmental variability. In Missouri, the stand persistence of birdsfoot trefoil (Lotus corniculatus), a perennial legume, is often limited by disease and poor seed production. A stage-based, matrix population model was developed to evaluate the population dynamics of birdsfoot trefoil in relation to clipping treatment. The plant growth stages represented in the model were seeds, seedlings, mature vegetative and reproductive plants. Two phases of population growth were evaluated in clipped and unclipped stands. Establishment-phase populations were characterized by relatively high mortality and low reproduction. Elasticity analysis indicated that growth of these populations was most sensitive to the survival of vegetative plants. Mature vegetative plants and seeds comprised the majority of surviving individuals in clipped and unclipped populations, respectively; however, establishment-phase populations under both management treatments tended toward extinction. Populations in the post-establishment phase of growth were characterized by relatively low mortality and high reproduction. Population growth in this phase of growth was most sensitive to seed production, and most individuals in these populations were at the seed stage.

********************

Establishment, growth and persistence of greater lotus (Lotus uliginosus) at six sites in eastern Australia.
Blumenthal, M.J.; Bowman, A.M.; Cole, A.; Jones, R.M.; Kelman, W.M.; Launders, T.E.; Nicol, H.I. 1999. Australian Journal of Experimental Agriculture Vol. 39:819-827.

Three Lotus uliginosus populations, cv. Maku, Sharnae and the line G4704 were compared to Trifolium repens cv. Haifa on the basis of plant frequency and contribution to total above ground biomass production at 6 sites in eastern Australia (Samford, Grafton, Taree, Nowra, Moss Vale and Warragul). In addition, L. uliginosus G4703 was sown at Nowra and L. corniculatus (L.) cv. Grasslands Goldie was sown at Taree. At each site populations were sown with a grass; Setaria sphacelata cv. Narok at Samford, Grafton and Taree; Lolium perenne cv. Kangaroo Valley at Nowra and Moss Vale and cv. Ellett at Warragul. Grasslands Maku and the sown grasses were also sown alone at each site. Each of the pasture treatments was sown either with 500 kg/ha single superphosphate or without superphosphate (or with small amounts of P, if available soil Bray P <16 mg/kg). The main findings were that: (i) superphosphate had little effect on lotus frequency and biomass after the first few harvests; (ii) Haifa white clover was the most successful legume in terms of plant frequency and contribution to total biomass at the subtropical sites (Taree, Grafton and Samford); (iii) Haifa was the most successful legume in the establishment year at the temperate sites, but lotus became dominant in subsequent years; (iv) Grasslands Maku was the superior greater lotus population in terms of frequency and contribution to total biomass production at all sites; and (v) at Taree, the one site where L. corniculatus cv. Grasslands Goldie was included, it was the superior population.

********************

Detecting decline in a formerly widespread species: how common is the common blue butterfly Polyommatus icarus?
Leon-Cortes, J.L.; Cowley, MJR.; Thomas, C.D. 1999. Ecography Vol. 22:643-650.

Grid square distribution maps have been used widely to measure rates of decline and target conservation resources, However, common species that may have many populations per grid square can decline substantially from within squares without being lost from entire squares. In order to quantify this process. fine scale population and habitat data have been collected for the common blue butterfly Polyommatus icarus in a 35 km(2) area of fragmented landscape in north Wales. Present day habitat associations, determined from over 2000 transect walks, combined with data on historical and present day habitat distributions reveal that the species has declined by about 74% since 1901. Similar data concerning the species major host plant Lotus corniculatus indicate a decline of 46%. Based on 1 km(2) grid maps, neither species have been assessed as declining at all. These results suggest that apparently 'common' species may have declined just as much as many of Britain's rare species: using present methods of assessment these declines are undetected.

********************

The effect of grazing Lotus corniculatus during late summer-autumn on reproductive efficiency and wool production in ewes.
Luque, A.; Barry, T.N.; McNabb, W.C.; Kemp, P.D.; McDonald, M.F. 2000. Australian Journal of Agricultural Research Vol. 51:385-391.

A grazing experiment was conducted at Massey University (Palmerston North, New Zealand) over 80 days in the late summer-autumn of 1998 (9 February-29 April). Reproductive performance and wool growth of ewes grazing on Lotus corniculatus (birdsfoot trefoil) were compared with those of ewes grazing perennial ryegrass-white clover pasture. A rotational grazing system with 210 mixed-age dry ewes (59.8+/-0.9 kg/ewe) was used, with 80 ewes grazing pasture [1 g of condensed tannin (CT) per kg dry matter (DM)] and 130 ewes grazing L. corniculatus (24 g CT/kg DM). Half of the ewes grazing L. corniculatus were supplemented orally, twice daily, with polyethylene glycol (PEG; MW, 3500) to inactivate the CTs. The effect of forage species and PEG supplementation on voluntary feed intake (VFI), reproductive performance (as measured by ovulation rate), and wool production was measured during 4 synchronised oestrous cycles. The ewes were restricted to maintenance feeding during the first 10 days of each oestrous cycle and then increased to ad libitum for the 6 days leading up to and including ovulation. In vitro organic matter digestibility in the selected diet was higher for lotus than for pasture (0.80 v. 0.76), with L. corniculatus containing less nitrogen than pasture (36.5 v. 40.8 g/kg organic matter). Ewes grazing on L. corniculatus produced 11% more wool and had an ovulation rate up to 14% higher than ewes grazing pasture, with neither parameter being affected by PEG supplementation. Higher mean ovulation rates of ewes grazing L. corniculatus were due to increases in fecundity (multiple ovulations/ovulating ewe; P < 0.05), with no effect on ewes cycling/ewes mated. Three cycles of grazing on L. corniculatus were required to achieve the maximum response in multiple ovulation, but most of this was achieved after 2 cycles. As the VFI of ewes grazing on L. corniculatus was not greater than that of ewes grazing pasture, the greater wool production and higher ovulation rate of ewes grazing this forage was due to improved efficiency of feed utilisation. It was concluded that feeding ewes L. corniculatus increased the efficiency of both reproduction and wool production without increasing VFI.

********************

Protein degradability and forage quality in maturing alfalfa, red clover, and birdsfoot trefoil.
Cassida, K.A.; Griffin, T.S.; Rodriguez, J.; Patching, S.C.; Hesterman, O.B.; Rust, S.R. 2000. Crop Science Vol. 40:209-215.

Choice of forage species and harvest management may influence protein degradability in cattle diets. We measured forage yield, undegradable intake protein (UIP), and forage quality at three maturities in two cuttings (spring, regrowth) of alfalfa (Medicago sativa L,), red clover (Trifolium pratense L.), and birdsfoot trefoil (Lotus corniculatus L.) in the seeding and two subsequent years. At equivalent harvest stage, trefoil and clover were usually lower in neutral detergent fiber (NDF) and acid detergent fiber (ADF) than alfalfa. Crude protein (CP) was lower in red clover than trefoil or alfalfa for three of six cuttings, but red clover was equal to or higher in UIP than alfalfa or trefoil in all cuttings. Trefoil never had higher UIP concentrations than alfalfa. Trefoil tannin concentrations increased with maturity and were positively correlated with UIP concentration. For all species, UIP was positively correlated with NDF and ADF and negatively correlated with in situ dry matter disappearance (ISDMD). In alfalfa and trefoil, UIP was negatively correlated with CP, In all legumes, dry matter yield (DMY), NDF, and ADF increased with maturity, while CP and ISDMD decreased. Changes in NDF, ADF, CP, and ISDMD with maturity were usually most rapid in trefoil. The proportion of UIP increased with maturity for all species in all cuttings, but it never comprised more than 240 g kg(^-1) CP. Small increases in UIP as legumes matured were gained at the expense of other forage quality measures.

********************

A new Mesorhizobium loti HAMBI 1129 phage isolated from Polish soil. Turska-Szewczuk, A.; Russa, R. 2000. Current Microbiology. Vol. 40: 341-343.
Phage A1 isolated from the rhizosphere of Lotus corniculatus was studied. It had a very narrow host range, as it was active only against Mesorhizobium loti HAMBI 1129. Phage A1 was classified as belonging to C Bradley's group bacteriophages. The latent period of A1 was 120-130 min and a burst size 13-17 particles per cell. The nature of the phage receptor was examined. Lipopolysaccharide from the phage-sensitive strain inactivated phage A1 in contrast to LPS from the phage-resistant bacteria. Purified LPS obtained from M. loti HAMBI 1129 had a high receptor activity with PhI50 value of 0.025 mu g/ml.

********************

The symbiosis island of a Mesorhizobium strain that nodulates lotus. Prokaryotic Nitrogen Fixation: a model system for the analysis of a biological process. Sullivan, J.T.; Trzebiatowski, J.R.; de Bruijn, F.J.; Ronson, C.W. 2000. Wymondham:Horizon Scientific Press. p. 693-704.

********************

A Lotus japonicus nodulation system based on heterologous expression of the fucosyl transferase NodZ and the acetyl transferase NolL in Rhizobium leguminosarum. Bras, C.P.; Jorda, M.A.; Wijfjes, AHM.; Harteveld, M.; Stuurman, N.; Thomas-Oates, J.E.; Spaink, H.P. 2000. Molecular Plant-Microbe Interactions. Vol. 13: 475-479.
Heterologous expression of NodZ and NoIL proteins in Rhizobium leguminosarum by. viciae led to the production of acetyl fucosylated lipo-chitin oligosaccharides (LCOs), indicating that the NoIL protein obtained from Mesorhizobium loti functions as an acetyl transferase. We show that the NoIL-dependent acetylation is specific for the fucosyl penta-N-acetylglucosamine species. In addition, the NoIL protein caused elevated production of LCOs, Efficient nodulation of Lotus japonicus by the NodZ/NoIL-producing strain was demonstrated. Nodulation efficiency was further improved by the addition of the ethylene inhibitor L-alpha-(2-aminoethoxyvinyl) glycine (AVG).

********************

Germination and initial root growth of four legumes as affected by landfill biogas atmosphere. Marchiol, L.; Cesco, S.; Pinton, R.; Zerbi, G. 2000. Restoration Ecology. Vol. 8:93-98.
The most important problem in the restoration of closed landfills is the production of toxic gases by decomposition of refuse. Such gases affect the root system of plants growing on these sites. The aim of the present study was to assess the effects induced by landfill biogas contamination on germination and initial root growth of Vicia villosa (hairy vetch), Lotus corniculatus (birdsfoot trefoil), Trifolium pratense (red clover), and Trifolium repens (white clover). In laboratory conditions, simulated landfill and control gas were supplied to the seedlings. The composition of the simulated landfill gas used was: 16% O-2, 8% CO2, 3% CH4, and 73% N-2; a control gas was also tested (21% O-2, 0. 035% CO2, and 78% N-2). Percentage of germinated seeds was determined after 6 and 12 days from the starting date; at the same time qualitative assays of metabolic root functionality were also performed by using an agar technique in order to visualize changes in rhizosphere pH. At the end of the experiment, the length of the primary and secondary root was measured. Germination after 6 days was affected by the gas treatment; the landfill biogas caused a delay in germination with respect to the control in seeds of V. villosa and L. corniculatus. Root fresh weight and dry weight were significantly decreased by biogas treatment in V. villosa and T. repens. In contrast, root dry weight was higher in gas treated L. corniculatus and T. pratense compared to control seedlings. Total root system was significantly higher in treated T. pratense. The qualitative assay suggests, with the exception of T. pratense, a metabolic adjustment of the treated seedlings.

********************

Cyanogenesis, herbivory and plant defense in Turnera ulmifolia on Jamaica. Schappert, P.J.; Shore, J.S. 1999. Ecoscience Vol. 6: 511-520.
Field surveys of eight populations of Turnera ulmifolia L., a Jamaican weed exhibiting quantitative genetic variation for cyanogenesis, were undertaken to assess the effectiveness of cyanogenesis as a plant defense. Populations known to be characteristically acyanogenic, cyanogenic or to exhibit within-population variation were surveyed for cyanogenesis, plant size, and the presence and identity of invertebrate plant visitors. A developmental series of 10 leaves from a shoot of each surveyed plant was analyzed, using image analysis techniques, for the type and extent of damage present. We also surveyed two additional plant populations for the presence of plants with eggs or larvae of Euptoieta hegesia Cramer, a Nymphalid butterfly that is potentially the most damaging herbivore of T. ulmifolia, and a paired comparison analysis of cyanogenesis in plants with the herbivore versus plants without the herbivore was conducted. We found that T. ulmifolia are attacked by a reasonably diverse insect fauna, but a relatively small suite of specialist herbivores that are seemingly undeterred by cyanogenesis inflicts most of the leaf damage. Cyanogenesis does appear to play a role in determining the types, numbers, and presence of generalist herbivores found within and between populations. Tissue loss sustained by plants varies both within and between populations; however, the proportion of leaf tissue lost due to herbivory is low, ranging from only 1-9% on average, and does not appear to be correlated with cyanogenesis in a consistent way. An analysis of covariance did, however, reveal that cyanogenesis has a significant effect on both plant height and number of shoots per plant. These results suggest that cyanogenesis might afford protection against herbivory from generalizing herbivores.

********************

Diverse mechanisms for CO2 effects on grassland litter decomposition. Dukes, J.S.; Field, C.B. 2000. Global Change Biology. Vol. 6:145-154.
The ongoing increase in atmospheric CO2 concentration ([CO2]) can potentially alter litter decomposition rates by changing: (i) the litter quality of individual species, (ii) allocation patterns of individual species, (iii) the species composition of ecosystems (which could alter ecosystem-level litter quality and allocation), (iv) patterns of soil moisture, and (v) the composition and size of microbial communities. To determine the relative importance of these mechanisms in a California annual grassland, we created four mixtures of litter that differed in species composition (the annual legume Lotus wrangelianus Fischer & C. Meyer comprised either 10% or 40% of the initial mass) and atmospheric [CO2] during growth (ambient or double-ambient). These mixtures decomposed for 33 weeks at three positions (above, on, and below the soil surface) in four types of grassland microcosms (fertilized and unfertilized microcosms exposed to elevated or ambient [CO2]) and at a common field site. Initially, legume-rich litter mixtures had higher nitrogen concentrations ([N]) than legume-poor mixtures. In most positions and environments, the different litter mixtures decomposed at approximately the same rate. Fertilization and CO2 enrichment of microcosms had no effect on mass loss of litter within them. However, mass loss was strongly related to litter position in both microcosms and the field. Nitrogen dynamics of litter were significantly related to the initial [N] of litter on the soil surface, but not in other positions. We conclude that changes in allocation patterns and species composition are likely to be the dominant mechanisms through which ecosystem-level decomposition rates respond to increasing atmospheric [CO2].

********************

Lupine leghemoglobin I: expression in transgenic Lotus and tobacco tissues. Strozycki, P.M.; Karlowski, W.M.; Dessaux, Y.; Petit, A.; Legocki, A.B. 2000. Molecular and General Genetics. Vol. 263:173-182.
The proximal parts of the promoters of the genes for symbiotic-type hemoglobins are generally conserved, but the promoter of the lbI gene of lupine (LulbI) shows some unusual structural features. It lacks typical organ-specific elements characteristic of all the leghemoglobin gene promoters described thus far. We have analysed its functional activity in transgenic Lotus corniculatus. A fusion construct between the lbI promoter and the GUS reporter gene was expressed mainly in the central zone of the root nodule, but the product was also detected in the non-nodule root zone and in roots in tissue culture. In roots of transgenic tobacco, the activity of the promoter was only 24% lower than in Lotus nodules. LulbI promoter activity was also detected in tobacco leaves. Lupine hemoglobin I has a higher sequence identity to symbiotic-type hemoglobins and thus it groups within the "Class II" hemoglobins.

********************

The effect of different ways and frequency of harvesting of set aside arable land on the weed infestation. Brant, V.; Santrucek, J.; Svobodova, M. 2000. Zeitschrift fur Pflanzenkrankheiten und Pflanzenschutz-Journal of Plant Diseases and Protection. p. 105-112.
The influence of different ways and frequency of harvesting (1 or 3 cuts with mass removing, 1 or 2 times mulching per year) on weed infestation in the stands of Bromus catharticus Vahl., Arrhenatherum elatius (L.) P.Beauv. ex J.S. et K.B. Presl, Festuca pratensis Huds., Dactylis aschersoniana Graebn., Trifoliun repens L., Medicago lupulina L., Lotus corniculatus L., Medicago media Pers. and fallow land was observed. The number of plants or stems of weeds and the dry mass yield were measured. Legume stands were most infested by weeds especially under the less frequency of harvesting (Medicago lupulina L., Trifolium repens L till 100 % of DM yield). Grasses were only very little infested. The three times cut stands were less infested compared to the others. Agropyron repens (L.) P.Beauv, Cirsium arvense (L.) Scop., Convolvulus arvensis L. and Lactuca serriola L. were the dominant weed species.

********************

A cladistic analysis of the Old World species of Lotus L. (Fabaceae:Loteae). Arambarri, A.M. 2000. Canadian Journal of Botany. Vol. 78: 351-360.

The diagnostic characters of the genus Lotus L. are a claw with a thickened infolded margin, diadelphous stamens, and a style hardened from the base. This genus contains about 100 species that are distributed throughout the world. To investigate the phylogeny of the Old World species of Lotus, subgenus Edentolotus, sections Krokeria, Xantholotus, and Erythrolotus, a cladistic analysis was performed using 31 morphological characters. To test the phylogenetic relationships among species of Lotus-Edentolotus and Dorycnium, Pedrosia, and Tetragonolobus, these taxa were included as part of the ingroup. The polarity of the characters was based on the outgroup comparison method, using Anthyllis as one outgroup and Tripodion as another. The analysis with Anthyllis as outgroup yielded eight equally parsimonious trees (with all characters equally weighted), each with 62 steps, a consistency index of 0.53, and a retention index of 0.75. All trees (including the strict consensus tree from the eight initial trees) showed that genus Lotus, subgenus Edentolotus, and sections Xantholotus and Erythrolotus are polyphyletic, with only section Krokeria appearing as monophyletic. On the other hand, the groups of species Lotus angustissimus, Lotus corniculatus, Lotus creticus, and Lotus peregrinus are monophyletic. Identical results were derived from the data matrix using Tripodion as the outgroup. Results are compared with previous cytogenetic and biochemical evidence.

********************

The effect of condensed tannins from seven herbages on Trichostrongylus colubriformis larval migration in vitro. Molan, A.L.; Waghorn, G.C.; Min, B.R.; McNabb, W.C. 2000. Folia Parasitologica. Vol. 47: 39-44.
The effects of condensed tannins (CT) extracted from seven forages on the motility of the economically important nematode, Trichostrongylus colubriformis (Giles, 1892), were evaluated by using a larval migration inhibition (LMI) assay. The assay involved incubation of third stage (L3) exsheathed T. colubriformis larvae with CT extracted from Lotus pedunculatus, Lotus corniculatus, sulla (Hedysarum coronarium), sainfoin (Onobrychis viciifolia), Dorycnium rectum, Dorycnium pentaphyllum and dock (Rumex obtusifolius) acid measurement of larval migration through nylon mesh with a 20 mu m pore size. At 100 mu g ml(-1), CT from L. pedunculatus L. corniculatus, sulla, sainfoin, D. rectum, D. pentaphyllum and dock inhibited 20%, 10%, 15%, 25%, 28%, 32% and 27% of the larvae, respectively from passing through the sieves compared to controls (no CT added). Al 1000 mu g CT ml(-1), CT purified from D. pentaphyllum had the highest inhibitory activity (63%) against 1-month old larvae followed by sainfoin (59%), L. Pedunculatus (57%), D rectum (53%), dock (50%), sulla (40%) and L. corniculatus (37%). Seven-month old larvae were more sensitive to the action of CT than 1-month old larvae (P < 0.001). Addition of 2 mu g polyethylene glycol ([PEG] per mu g CT; to remove the effect of CT) eliminated 81-93% of the CT activity (P < 0.001) compared to incubations without PEG. The impact of CT on larval migration suggests a possible role for these plants in ruminant diets as a means to reduce dependence upon proprietary anthelmintics.

********************

Soil water dynamics and growth of perennial pasture species for dryland salinity control. Lolicato, S.J. 2000. Australian Journal of Experimental Agriculture. Vol. 40:37-45.
Fortnightly soil water content measurements to a depth of 2.1 m under 4 cocksfoot cultivars, 2 phalaris cultivars, 2 lucerne cultivars and 1 Lotus corniculatus cultivar were used to compare soil profile drying and to define seasonal patterns of plant water use of the species over a 3-year period, on a duplex soil. Cultivars were also selected, within species groups, for varying seasonal growth patterns to assess this influence on soil water dynamics and growth. Over the 3-year period, treatments with the highest and lowest measures of profile soil water content were used to derive and compare values of maximum plant extractable water. Plots were maintained for a further 3 years, after which soil water content measurements in autumn were used to assess long-term effects of the treatments. The effect of seasonal growth patterns within a species was negligible; however, there were significant differences between species. Twenty-one months after pasture establishment, lucerne alone had a drying effect at 2.0 m depth and subsequently it consistently showed profiles with the lowest soil water content. Maximum plant extractable water was greatest for lucerne (230 mm), followed by phalaris (210 mm), Lotus corniculatus (200 mm) and cocksfoot (170 mm). Profiles with the lowest soil water content were associated with greater herbage growth and greater depths of water extraction. The soil water deficits developed by the treatments in autumn of the fourth year were similar to those measured in autumn of the seventh year, implying that a species-dependant equilibrium had been reached. Long-term rainfall data is used to calculate the probabilities of recharge occurring when rainfall exceeds maximum potential deficits for the different pasture species.

********************

Mesorhizobium loti increases root-specific expression of a calcium-binding protein homologue identified by promoter tagging in Lotus japonicus. Webb, K.J.; Skot, L.; Nicholson, M.N.; Jorgensen, B.; Mizen, S. 2000. Molecular Plant-Microbe Interactions. Vol. 13:606-616.
A promoter tagging program in the legume Lotus japonicus was initiated to identify plant genes involved in the nitrogen-fixing symbiosis between legumes and rhizobia, Seven transformed plant lines expressing the promoterless reporter gene uidA (beta-glucuronidase; GUS) specifically in roots and/or nodules were identified. Four of these expressed GUS in the roots only after inoculation with nodule-forming Mesorhizobium loti, In one line (T90), GUS activity was found in the root epidermis, including root hairs. During seedling growth, GUS expression gradually became focused in developing nodules and disappeared from root tissue. No GUS activity was detected when a non-nodulating mutant of ill. loll was used to inoculate the plants. The T-DNA insertion in this plant line was located 1.3 kb upstream of a putative coding sequence with strong homology to calcium-binding proteins. Four motifs were identified, which were very similar to the "EF hands" in calmodulin-related proteins, each binding one Ca2+. We have named the gene LjCbp1 (calcium-binding protein). Northern (RNA) analyses showed that this gene is expressed specifically in roots of L. japonicus. Expression was reduced in roots inoculated with non-nodulating M. loti mutants and in progeny homozygous for the T-DNA insertion, suggesting a link between the T-DNA insertion and this gene.

********************

Water-selective and multifunctional aquaporins from Lotus japonicus nodules. Guenther, J.F.; Roberts, D.M. 2000. Planta. Vol. 210:741-748.
By using reverse transcriptase-polymerase chain reaction, two cDNAs were isolated that encode major intrinsic membrane proteins (MIPs) that are expressed in nitrogen-fixing root nodules of Lotus japonicus. Lotus intrinsic membrane protein 1 (LIMP 1) is expressed at high levels in both nodule and root tissues and shows highest sequence similarity to members of the tonoplast intrinsic protein (TIP) subfamily of plant MIPs. Functional analysis of LIMP 1 by expression in Xenopus laevis oocytes show that it is a water-specific aquaporin. In contrast, LIMP 2 shows the highest sequence similarity to soybean nodulin 26 (67.8% amino acid sequence identity). LIMP 2 is also a nodulin, showing expression only in mature nitrogen fixing nodules of L. japonicus. LIMP 2 is a multifunctional aquaglyceroporin, and displays the ability to flux both water as well as glycerol upon expression in Xenopus oocytes. Additionally, the carboxyl terminal region of LIMP 2 has a conserved phosphorylation motif that is phosphorylated by a calmodulin-like domain protein kinase. Overall, the data show that L. japonicus nodules contain two structurally and functionally distinct MIP proteins: one (LIMP 2) which appears to be the nodulin 26 ortholog of L. japonicus and another (LIMP 1) which appears to be a member of the TIP subfamily.

********************

Is there a genetic basis for fluctuating asymmetry and does it predict fitness in the plant Lotus corniculatus grown in different environmental conditions? Andalo, C.; Bazin, A.; Shykoff, J.A. 2000. International Journal of Plant Sciences. Vol. 161:213-220.
Fluctuating asymmetry (FA) is considered to be a good measure of developmental stability. We measured the asymmetry of leaves and flowers of 16 different genotypes of Lotus corniculatus grown in four different experimental environments to estimate the plasticity or developmental stability of asymmetry itself. We found that an index of FA (absolute difference between size of left and right sides, corrected for trait size) differed significantly across environments, with the treatment CO2+/N+ inducing the greatest FA for both flowers and leaves. Genotypes did not differ in FAs. Individual plants showed significantly different FAs only for flowers. At the individual level, we found no significant relationship between flower FA and fitness. Previous work indicates that change in asymmetry in a poor or perturbing environment Versus a good environment could reflect the intrinsic quality of a particular genotype. However, in our experiment, genotype effect was significant only for change in asymmetry of leaves, and this last trait was not significantly correlated with our fitness estimate for each genotype in either the most or the least perturbing environment.

********************

Isolation of two different phenotypes of mycorrhizal mutants in the model legume plant Lotus japonicus after EMS-treatment. Senoo, K.; Solaiman, M.Z.; Kawaguchi, M.; Imaizumi-Anraku, H.; Akao, S.; Tanaka, A.; Obata, H. 2000. Plant and Cell Physiology. Vol. 41:726-732.
Lotus japonicus has been proposed as a model plant for the molecular genetic study of plant-microbe interaction including Mesorhizobium loti and arbuscular mycorrhizal (AM) fungi. Non-mycorrhizal mutants of Lotus japonicus were screened from a collection of 12 mutants showing non-nodulating (Nod(-)), ineffectively nodulating (Fix(-)) and hypernodulating (Nod(++)) phenotypes with monogenic recessive inheritance induced by EMS (ethylmethane sulfonate) mutagenesis, Three mycorrhizal mutant lines showing highly reduced arbuscular mycorrhizal colonization were obtained. All of them were derived from Nod- phenotypes. In Ljsym72, the root colonization by Glomus sp. R-10 is characterized by poor development of the external mycelium, formation of extremely branched appressoria, and the blocking of hyphal penetration at the root epidermis. Neither arbuscules nor vesicles were formed in Ljsym72 roots. Fungal recognition on the Foot surface was strongly affected by the mutation in the LjSym72 gene. Unique characteristics in mutant lines Ljsym71-1 and Ljsym71-2 were the overproduction of deformed appressoria and arrested hyphal penetration of the exodermis, Small amounts of internal colonization including degenerated arbuscule formation occurred infrequently in these types of mutants. Not only fungal development on the root surface but also that in the root exodermis and cortex was affected by the mutation in LjSym71 gene. These mutants represent a key advance in molecular research on the AM symbiosis.

********************

Alternative home-grown protein sources for ruminants in the United Kingdom. Wilkins, R.J.; Jones, R. 2000. Animal Feed Science and Technology. Vol. 85:23-32.
Improved sources of home-grown protein are required to substitute for animal proteins and soyabean meal in ruminant feeds. The present dominance of grassland feeds for protein supply in Britain is highlighted and possibilities for increasing microbial protein (MP) supply on grass-based diets are considered. There are particular opportunities for improving MP supply and animal performance from the use of grasses with increased content of water-soluble carbohydrates (WSC) and by the prevention of WSC and protein breakdown during ensiling through the use of bacterial inocula or chemical additives to restrict fermentation. Potential contributions from legumes and kale as alternative forages are reviewed. Whilst white clover and lucerne may give higher levels of MP than grass, this arises largely from high herbage protein concentration and high levels of feed intake, with large quantities of N being lost in excreta. There is evidence of natural protection of protein in red clover from polyphenol oxidase and in lotus and sainfoin by condensed tannins. These attributes may result in improved protein supply to the animal, but further research is required, particularly with silages. The grain legumes, peas and beans are not ideal protein supplements for grass silage because of their rapid degradation in the rumen, but are more suited as supplements to maize silage with low content of protein and good supply of readily available energy. Progress in plant breeding has opened up the possibility of increased use in Britain of lupins, which have much lower rates of degradation in the rumen than peas and beans and should form an effective complement to grass silage.

********************

Solubilization and degradation of ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39; Rubisco) protein from white clover (Trifolium repens) and Lotus corniculatus by rumen microorganisms and the effect of condensed tannins on these processes. Min, B.R.; McNabb, W.C.; Barry, T.N.; Peters, J.S. 2000. Journal of Agricultural Science. Vol. 134:305-317.
In situ and in vitro rumen incubations were used to determine the effect of condensed tannins (CT) on the solubilization and degradation of the plant protein from white clover (Trifolium repens) and Lotus corniculatus. These forages contained, respectively 0.3 and 22.1 g CT/kg dry matter (DM). The sheep used for the experiments were also fed either white clover or L. corniculatus. Effects of CT were determined by making measurements in the presence and absence of polyethylene glycol (PEG; molecular weight 3500), which binds and inactivates CT. The loss of DM, neutral detergent fibre (NDF), total nitrogen (N) and Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase; EC 4.1.1.39; fraction I leaf protein) from polyester bags suspended in the rumen of sheep was measured. The loss of these constituents from polyester bags suspended in the rumen was used as a measurement of their solubilization. Degradation was defined as the disappearance of Rubisco from white clover and L. corniculatus added to in vitro incubations with rumen fluid obtained from the same fistulated sheep fed either white clover or L. corniculatus. In the absence of PEG, the in situ loss of Rubisco from L. corniculatus was less rapid than the loss of this protein from white clover when each forage was incubated in the rumen of sheep fed the same diet. Addition of PEG tended to increase the loss of Rubisco from L. corniculatus, suggesting that CT slowed the rates of solubilization of Rubisco from this forage. Effects of rumen fluid were small, but there was some evidence that the rumen fluid in sheep fed L. corniculatus reduced the solubilization of Rubisco from white clover. The action of CT did not inhibit the in situ loss of NDF from either white clover or L. corniculatus. In the absence of PEG, the in vitro degradation of Rubisco from L. corniculatus was slower when compared to the degradation of this protein from white clover; PEG addition increased the degradation of Rubisco from L. corniculatus, but not from white clover, showing that CT was the causal agent. The addition of CT extracted from L. corniculatus markedly depressed the degradation of Rubisco from white clover, with the effect being completely reversible by PEG. The large subunit (LSU) of Rubisco was consistently degraded at a faster rate than the small subunit (SSU) and added CT had a greater effect in slowing the degradation of the LSU compared to the SSU. There was little difference in the degradation of Rubisco when rumen fluid from sheep fed either white clover or L. corniculatus was used for in vitro incubations. It was concluded that the action of CT from L. corniculatus reduces the digestion of protein in the rumen of sheep. This effect is predominantly due to the action of CT reducing the degradation of plant protein, although CT also reduced the solubilization of plant protein. The main effects of CT on protein solubilization and degradation seemed to be produced locally by CT present in plant tissue; transfer of these effects through rumen fluid was small in magnitude.

********************

Characterization of an atrazine-degrading Pseudaminobacter sp isolated from Canadian and French agricultural soils. Topp, E.; Zhu, H.; Nour, S.M.; Houot, S.; Lewis, M.; Cuppels, D. 2000. Applied and Environmental Microbiology. Vol. 66:2773-2782.
Atrazine, a herbicide widely used in corn production, is a frequently detected groundwater contaminant. Fourteen bacterial strains able to use this herbicide as a sole source of nitrogen were isolated from soils obtained from two farms in Canada and two farms in France. These strains were indistinguishable from each other based on repetitive extragenic palindromic PCR genomic fingerprinting performed with primers ERIC1R, ERIC2, and BOXA1R. Based on 16S rRNA sequence analysis of one representative isolate, strain C147, the isolates belong to the genus Pseudaminobacter in the family Rhizobiaceae, Strain C147 did not form nodules on the legumes alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), red clover (Trifolium pratense L.), chickpea (Cicer arietinum L.), and soybean (Glycine max L.). A number of chloro-substituted s-triazine herbicides were degraded, but methylthio-substituted s-triazine herbicides were not degraded. Based on metabolite identification data, the fact that oxygen was not required, and hybridization of genomic DNA to the atzABC genes, atrazine degradation occurred via a series of hydrolytic reactions initiated by dechlorination and followed by dealkylation. Most strains could mineralize [ring-U-C-14] atrazine, and those that could not mineralize atrazine lacked atzB or atzBC. The atzABC genes, which were plasmid borne in every atrazine-degrading isolate examined, were unstable and were not always clustered together on the same plasmid. Loss of atzB was accompanied by loss of a copy of IS1071. Our results indicate that an atrazine-degrading Pseudaminobacter sp. with remarkably little diversity is widely distributed in agricultural soils and that genes of the atrazine degradation pathway carried by independent isolates of this organism are not clustered, can be independently lost, and may be associated with a catabolic transposon, We propose that the widespread distribution of the atrazine-degrading Pseudaminobacter sp. in agricultural soils exposed to atrazine is due to the characteristic ability of this organism to utilize alkylamines, and therefore atrazine, as sole sources of carbon when the atzABC genes are acquired.

********************

Manipulating the pathway of ammonia assimilation through genetic engineering and breeding: consequences to plant physiology and plant development. Harrison, J.; Brugiere, N.; Phillipson, B.; Ferrario-Mery, S.; Becker, T.; Limami, A.; Hirel, B. 2000. Plant and Soil. V 221:81-93.
In this article we discuss the ways in which our understanding of the nature of the molecular controls of nitrogen assimilation have been increased by the use of leguminous and non-leguminous plants with modified capacities for ammonium assimilation. These modifications have been achieved through genetic engineering and breeding. An improved understanding of nitrogen assimilation will be vital if improvements in crop nitrogen use efficiency are to be made to reduce the need for excessive input of fertilisers. In this review we present an overall view of past work and more recent studies on this topic. In our work, using tobacco and Lotus as model plants, glutamine synthetase and glutamate synthase activites have been altered by stimulating or inhibiting in an organ- or tissue-specific manner the expression of the corresponding genes. The physiological impact of these genetic manipulations has been studied on plants grown under different nitrogen regimes.

********************

Effects of short-term exposure to condensed tannins on adult Trichostrongylus colubriformis. Athanasiadou, S.; Kyriazakis, I.; Jackson, F.; Coop, R.L. 2000. Veterinary Record. V 146:728-732.
Twelve parasite-naive sheep were used to study the possible direct anthelmintic effect of a condensed tannin extract (quebracho) on the population and fecundity of the intestinal nematode Trichostrongylus colubriformis. The sheep were infected with a single dose of 20,000 L-3 of T. colubriformis. Twenty-eight days later, six of them were drenched daily for a week with quebracho extract at 8 per cent by weight of their food intake. All lambs were then slaughtered, and their small intestines removed to estimate the worm burdens and the numbers of eggs in utero. Two days after the first drench with tannin extract the faecal egg counts of the treated sheep were approximately 50 per cent of those of the control sheep (P<0.01), but there was no further reduction with continued drenching. In the treated sheep the worm burdens and number of eggs per gram faeces per worm were reduced by 30 per cent compared with the controls (P<0.05), but the sex ratios, the number of eggs in utero and length of the worms were not affected by drenching with tannin.

********************

Polymorphism in cyanogenic glycoside content and cyanogenic beta-glucosidase activity in natural populations of Eucalyptus cladocalyx. Gleadow, R.M.; Woodrow, I.E. 2000. Australian Journal of Plant Physiology. V 27:693-699.
Cyanogenesis is the process by which plants release hydrogen cyanide (HCN) from endogenous cyanide-containing compounds and is thought to play a role in plant defence against generalist herbivores. Cyanogenesis is poorly understood in natural populations, and has been little studied in tree species. In this paper we present the first systematic survey of cyanogenesis in the economically and ecologically important genus Eucalyptus. We document variability in both the concentration of the cyanogenic glycoside, prunasin, and the accompanying degradative beta-glucosidase in a woody plant for the first time. Leaves of 96 E. cladocalyx F. Muell. trees growing in natural populations on Kangaroo Island, South Australia were analysed. All trees were cyanogenic, containing both cyanogenic glycosides and active beta-glucosidase. Cyanogenic glycoside concentration varied by over two orders of magnitude. The beta-glucosidase activity varied widely as well, but plants high in cyanogenic glycosides did not necessarily have higher enzyme activity. A significant proportion of the variation in cyanogenic glycoside concentration can be accounted for by the variation in leaf nitrogen. Most of the variation, however, appears to be the result of genetic polymorphism, which is inherited independently of the level of activity of the degradative beta-glucosidase.

********************

Leaf pubescence, water relations and chlorophyll fluorescence in two subspecies of Lotus creticus L. Save, R.; Biel, C.; de Herralde, F. 2000. Biologia Plantarum. V 43:239-244.
The objective of the present study was to compare the plant morphology, water relations and photochemical efficiency of photosystem 2 in two wild Mediterranean species Lotus creticus creticus and Lotus creticus cytisoides. L. creticus creticus showed higher density of trichomes and stomatal density on the adaxial leaf surface than L. creticus cytisoides, whereas L. creticus cytisoides showed higher stomatal density in abaxial surface than L. creticus creticus. These morphological traits promoted clear differences in leaf surface water retention and leaf reflectance. Leaf water potential and photochemical efficiency were lower in L. creticus cytisoides than in L. creticus creticus.

********************

Effect of polyethylene glycol on in vitro degradability of nitrogen and microbial protein synthesis from tannin-rich browse and herbaceous legumes. Getachew, G.; Makkar, HPS.; Becker, K. 2000. British Journal of Nutrition. V 84:73-83.
Determination of microbial degradability of N is important in formulating a sound supplementation strategy for efficient utilisation of basal as well as supplementary diet components. In vitro degradability of N (IVDN) from tannin-containing browses (Acacia cyanophylla, Acacia albida, Acioa barteri and Quercus ilex) and two herbaceous legumes (Desmodium intortum and Desmodium uncinatum) was determined using the in vitro gas-production method coupled with NH3-N measurement in the presence and absence of a tannin-binding agent (polyethylene glycol (PEG), molecular mass 6000). Addition of PEG to tannin-containing feeds significantly (P < 0.05) increased in vitro gas and short-chain fatty acid (SCFA) production, and IVDN. The use of PEG as a tannin-binding agent increased IVDN from 28 to 59, 32 to 72, 19 to 40, 32 to 73, 40 to 80, and 26 to 77 % in A. cyanophylla, A. albida, A. barteri, D. intortum, D. uncinatum and Q. ilexrespectively. There was significant correlation between total phenolic compounds (total phenol, TP; total tannin, TT) in leguminous forages and percentage increase in IVDN on addition of PEG (P < 0.05; R-2 0.70 and 0.82 for TP and TT respectively). The difference in IVDN observed in the absence and presence of PEG indicates the amount of protein protected from degradation in the rumen by tannins. When measured after 24 h incubation, tannin-containing feeds incubated in absence of PEG resulted in higher microbial protein synthesis than in the presence of PEG. Addition of PEG significantly (P < 0.05) reduced the efficiency of microbial protein synthesis expressed as mu mol purine/mmol SCFA.

********************

Effects of ethylene precursor and inhibitors for ethylene biosynthesis and perception on nodulation in Lotus japonicus and Macroptilium atropurpureum. Nukui, N.; Ezura, H.; Yuhashi, K.I.; Yasuta, T.; Minamisawa, K. 2000. Plant and Cell Physiology. V 41:893-897.
Inhibitors of ethylene synthesis or its physiological function enhanced nodulation in Lotus japonicus and Macroptilium atropurpureum. In contrast, the application of 1-aminocyclopropane-1-carboxylic acid, a precursor of ethylene biosynthesis, reduced the nodule number in these legumes. These results suggest that an ethylene-mediated signaling pathway is involved in the nodulation process even in the determinate nodulators.

********************

Effect of forage legumes containing condensed tannins on lungworm (Dictyocaulus sp.) and gastrointestinal parasitism in young red deer (Cervus elaphus). Hoskin, S.O.; Wilson, P.R.; Barry, T.N.; Charleston, WAG.; Waghorn, G.C. 2000. Research in Veterinary Science. V 68:223-230.
To investigate the effect of feeding forage legumes containing condensed tannins (CT) on internal parasitism, red deer calves were fed either lucerne (Medicago sativa; 0.1 per cent CT), birdsfoot trefoil (Lotus corniculatus; 1.9 per cent CT) or sulla (Hedysarum coronarium; 3.5 per cent CT) and trickle-infected with deer-origin gastrointestinal nematode and lungworm (Dictyocaulus sp.) larvae for 5 weeks, then slaughtered at 7 weeks. There was a significant negative linear relationship between dietary CT concentration and abomasal nematode burdens. No significant differences in faecal egg counts, lungworm burdens or voluntary feed intake were found. Deer fed sulla had higher liveweight gain, carcass weight and carcass dressing-our percentage, higher serum total protein and albumin concentration and lower serum gastrin concentration and faecal lungworm larval count, compared with lucerne-fed deer. Inclusion of sulla in diets for young red deer may reduce the impact of internal parasites and/or reduce the dependence on anthelmintic treatment.

********************

Transplantation of the subshrub Lotus scoparius: Testing the home-site advantage hypothesis. Montalvo, A.M.; Ellstrand, N.C. 2000. Conservation Biology. V 14:1034-1045.
The long-term success of restored populations may be jeopardized by the collection locality of transplants if they are ill matched to their new environment. The home-site advantage hypothesis predicts that the relative success of introduced populations will decrease as their genetic and environmental distance to the local native population increases. We evaluated this hypothesis for a geographically variable shrub, Lotus scoparius, in southern Californian coastal sage scrub by planting two common-garden experiments with seedlings from 12 source populations. The common-garden sites differed in environment and were each home to different source populations of the two taxonomic varieties, L. s. var. scoparius or L. s. var. brevialatus. We used allozyme data from each source population to calculate genetic distances between populations, and a combination of climatic data and soil traits to calculate environmental distances. At the more mesic, coastal common garden, cumulative fitness of transplants (survival x flower production) was inversely related to genetic distance between source and resident populations. At the more xeric, inland common garden, cumulative fitness (survival x size) decreased significantly with both genetic and environmental distance after one taxonomic variety was excluded from analyses. Geographic distance was only weakly correlated with genetic distance and had little value in predicting cumulative fitness of transplants. Our data support the home-site advantage hypothesis and the idea that mis-matching source populations of these genetically differentiated seed sources may result in lowered success of restored or constructed populations. The genetic and environmental similarities of source populations should be considered when source materials are chosen for transplantation.

********************

Postburning legume seeding in the Flooding Pampas, Argentina. Juan, V.F.; Monterroso, L.; Sacido, M.B.; Cauhepe, M.A. 2000. Journal of Range Management. V 53:300-304.
In Argentina, Paspalum quadrifarium Lam. (paja colorada) forms tall dense grassland communities in the flooding pampas. Referred to locally as "pajonales", these grasslands generally have very low nutritional value for cattle, except at the post-burn regrowth stage. To improve forage quality and consumption by breeding cattle, Lotus tenuis Waist et Kit. is over seeded immediately after burning of paja colorada pajonales. The objectives of this experiment were to follow the after seeding cover of lotus, evaluate weed control, and assess disease incidence and severity. The experiment was carried out in Azul, Buenos Aires province of Argentina, between September 1993 to September 1996. The postburn seedbed was very favorable for lotus germination and establishment. The most effective chemical weed control was obtained with 2,4-DB used alone or in combination with dicamba. Lotus increased markedly the quality of the pasture forage due to its high crude protein content. Four fungus diseases were found: Botrytis cinerea Pers., Stemphylium sp. Wallroth, Uromyces loti Blytt. and Fusarium spp. Link ex Fr. However, these caused only light foliar damage and did not impair lotus germination or establishment. The overseeding of lotus after burning of P. quadrifarium pajonales, is a very effective technique to improve carrying capacity and animal performance.

********************

Short root mutant of Lotus japonicus with a dramatically altered symbiotic phenotype. Wopereis, J.; Pajuelo, E.; Dazzo, F.B.; Jiang, Q.Y.; Gresshoff, P.M.; de Bruijn, F.J.; Stougaard, J.; Szczyglowski, K. 2000. Plant Journal. V 23:97-114.
Legume plants carefully control the extent of nodulation in response to rhizobial infection. To examine the mechanism underlying this process we conducted a detailed analysis of the Lotus japonicus hypernodulating mutants, har1-1, 2 and 3 that define a new locus, HYPERNODULATION ABERRANT ROOT FORMATION (Har1), involved in root and symbiotic development. Mutations in the Har1 locus alter root architecture by inhibiting root elongation, diminishing root diameter and stimulating lateral root initiation. At the cellular level these developmental alterations are associated with changes in the position and duration of root cell growth and result in a premature differentiation of har1-1 mutant root. No significant differences between har1-1 mutant and wild-type plants were detected with respect to root growth responses to 1-aminocyclopropane1-carboxylic acid, the immediate precursor of ethylene, and auxin; however, cytokinin in the presence of AVG (aminoetoxyvinylglycine) was found to stimulate root elongation of the har1-1 mutant but not the wild-type. After inoculation with Mesorhizobium loti, the har1 mutant lines display an unusual hypernodulation (HNR) response, characterized by unrestricted nodulation (hypernodulation), and a concomitant drastic inhibition of root and shoot growth. These observations implicate a role for the Har1 locus in both symbiotic and non-symbiotic development of L. japonicus, and suggest that regulatory processes controlling nodule organogenesis and nodule number are integrated in an overall mechanism governing root growth and development.

********************

Effect of condensed tannins extracted from four forages on the viability of the larvae of deer lungworms and gastrointestinal nematodes. Molan, A.L.; Hoskin, S.O.; Barry, T.N.; McNabb, W.C. 2000. Veterinary Record. V 147:44-48.
The inhibitory activity of condensed tannins extracted from four forage legume plants were evaluated by using a larval migration inhibition assay. The first (L1) and third (L3) stages of deer lungworm (Dictyocaulus viviparus), and the third stage (L3) of deer gastrointestinal nematodes were incubated with tannins extracted from Lotus pedunculatus, Lotus corniculatus, sulla (Hedysarum coronorium) and sainfoin (Onobrychus viciifolia). The tannins extracted from all the forages had inhibitory activity as measured by their ability to paralyse the larvae and inhibit them from passing through sieves. At the highest concentration used (1200 mu g/ml) the tannins extracted from sainfoin had the highest activity against ensheathed L1 lungworm larvae (58 per cent), followed by L pedunculatus (45 per cent), sulla (42 per cent) and L corniculatus (35 per cent) when the larvae were incubated at 37 degrees C. The same trend, but with lower activities, was observed when the larvae were incubated at 22 degrees C. Anthelmintic activity against L3 lungworm larvae was evaluated by measuring the death rate of ensheathed L3 larvae after incubation with condensed tannins for two, 24 and 48 hours at room temperature (22 degrees C). The death rate was significantly higher (P<0.001) after 48 hours incubation than after two hours or 24 hours, and significantly higher (P<0.001) after 24 hours than after two hours incubation. Condensed tannins from sainfoin had the highest inhibitory activity followed by L pedunculatus, sulla and L corniculatus. The tannins from sainfoin also had the highest activity against L3 larvae of gastrointestinal nematodes, followed by L pedunculatus, sulla and L corniculatus. Exsheathed larvae of gastrointestinal nematodes were significantly more susceptible to the action of the tannins than ensheathed larvae.

********************

Effect of crop rotation and soil cover on alteration of the soil microflora generated by the culture of transgenic plants producing opines. Oger, P.; Mansouri, H.; Dessaux, Y. 2000. Molecular Ecology. V 9:881-890.
The culture of transgenic Lotus corniculatus plants producing opines, which are bacterial growth substrates, leads to the selection of rhizospheric bacteria able to utilize these substrates. We have investigated the fate of the opine-utilizing community over time under different experimental conditions following elimination of selective pressure exerted by the transgenic plants. These plants were removed from the soil, which was either left unplanted or replanted with wild-type L. corniculatus or wheat plants. The density of opine-utilizing bacteria in the fallow soils remained essentially unchanged throughout the experiment, regardless of the soil of origin (soil planted with wild-type or transgenic plants). When wild-type Lotus plants were used to replace their transgenic counterparts, only the bacterial populations able to utilize the opines were affected. Long-term changes affecting the opine-utilizing bacterial community on Lotus roots was dependent upon the opine studied. The concentration of nopaline utilizers decreased, upon replacement of the transgenic plants, to a level similar to that of normal plants, while the concentration of mannopine utilizers decreased to levels intermediate between transgenic and normal plants. These data indicate that: (i) the opine-utilizing bacterial populations can be controlled in the rhizosphere via plant-exudate engineering; (ii) the interaction between the engineered plants and their root-associated micro-organisms is transgene specific; and (iii) alterations induced by the cultivation of transgenic plants may sometimes be persistent. Furthermore, opine-utilizing bacterial populations can be controlled by crop rotation. Therefore, favouring the growth of a rhizobacterium of agronomic interest via an opine-based strategy appears feasible.

********************

Invasion and reproduction of Pratylenchus penetrans in birdsfoot trefoil cultivars. Kimpinski, J.; Papadopoulos, Y.A.; Christie, B.R.; McRae, K.B.; Gallant, C.E. 2000. Phytoprotection. V 80:179-184.
Greenhouse trials were conducted to determine the levels of invasion of birdsfoot trefoil (Lotus corniculatus) cultivars and lines by the root-lesion nematode (Pratylenchus penetrans). Numbers of nematodes in roots grown in 50-cm(3) polystyrene starter pots were determined 6 weeks after planting. Nematodes were detected in the roots of all cultivars and lines, though the degree of invasion varied significantly. In the first screening trial, carried out in 1994 on 23 cultivars and lines, NB90-104, Upstart, and Viking harbored the lowest population densities of nematodes with levels below 1 000 g(-1) of dry root, while Fergus and EPF had population densities over 30 000 g(-1) of dry root. In the second screening trial conducted in 1995, all nine cultivars and lines tested, including NB90-104, Upstart, and Viking, had nematode levels greater than 7 900 g(-1) of dry root. The results indicated that the cultivars and lines tested in this study exhibited wide genetic variability for invasion by root-lesion nematodes.

********************

Symbiotic N-2 fixation of various legume species along an altitudinal gradient in the Swiss Alps. Jacot, K.A.; Luscher, A.; Nosberger, J.; Hartwig, U.A. 2000. Soil Biology & Biochemistry. V 32:1043-1052.
Symbiotic N-2 fixation may be an important source of N for legumes in alpine ecosystems, though, this has hardly been investigated. Symbiotic N-2 fixation in nine legume species in permanent grassland over an altitudinal gradient (from 900 up to 2600 m a.s.l.) was investigated in the Swiss Alps on strictly siliceous soils. To assess symbiotic N-2 fixation, an enriched N-15 isotope dilution method was established for low N input, permanent grasslands and was evaluated with the N-15 natural abundance method. The non-N-2-fixing reference species used in both methods differed significantly in their N-15 atom%-excess. However, when several reference species were combined, the enriched N-15 isotope dilution method was reliable and led to the conclusion that up to their altitudinal limit, legumes may acquire from 59% to more than 90% of their N through symbiotic N-2 fixation depending on the species. These findings were confirmed by the N-15 natural abundance method. Even at the legumes' altitudinal limit all plants investigated showed apparently active nodules. Moreover, a clear host-microsymbiont specificity between plant and rhizobia was evident at high altitudes. This suggests that symbiotic N-2 fixation is well adapted to the climatic and acidic soil conditions in the Alps and contributes, up to the altitudinal limit, a significant amount of N to the N nutrition of legumes.

********************

New combinations in Acmispon (Leguminosae, Loteae). Sokoloff, D. 2000. Annales Botanici Fennici. V 37:125-131.
Seven new combinations in Acmispon Raf. are proposed. The diagnostic characters and tribal position of the genus are discussed. A complete list of accepted Acmispon species is presented. The genus comprises eight species belonging to two sections. Seven species occur in North America, with the center of diversity along the west coast, primarily in California. One species is endemic to Chile.

********************

Lotus japonicus contains two distinct ENOD40 genes that are expressed. Flemetakis, E.; Kavroulakis, N.; Quaedvlieg, NEM.; Spaink, H.P.; Dimou, M.; Roussis, A.; Katinakis, P. 2000. Molecular Plant-Microbe Interactions. V 13:987-994.
ENOD40, an early nodulin gene, has been postulated to play a significant role in legume root nodule ontogenesis, We have isolated two distinct ENOD40 genes from Lotus japonicus, The transcribed regions of the two ENOD40 genes share 65% homology, while the two promoters showed no significant homology, Both transcripts encode a putative dodecapeptide similar to that identified in other legumes forming determinate nodules, Both ENOD40 genes are coordinately expressed following inoculation of roots with Mesorhizobium loti or treatment with purified Nod factors. In the former case, mRNA accumulation could be detected up to 10 days following inoculation while in the latter case the accumulation was transient. High levels of both ENOD40 gene transcripts were found in nonsymbiotic tissues such as stems, fully developed flowers, green seed pods, and hypocotyls. A relatively lower level of both transcripts was observed in leaves, roots, and cotyledons. In situ hybridization studies revealed that, in mature nodules, transcripts of both ENOD40 genes accumulate in the nodule vascular system; additionally, in young seed pods strong signal is observed in the ovule, particularly in the phloem and epithelium, as well as in globular stage embryos.

********************

A review of the effects of forage condensed tannins on ruminal fermentation and bloat in grazing cattle. McMahon, L.R.; McAllister, T.A.; Berg, B.P.; Majak, W.; Acharya, S.N.; Popp, J.D.; Coulman, B.E.; Wang, Y.; Cheng, K.J. 2000. Canadian Journal of Plant Science. V 80:469-485.
Condensed tannins (CT) are polyphenolic secondary plant products that are widespread in the plant kingdom. By definition, CT bind to protein and are regarded as "antinutritional" compounds which reduce protein digestibility. Variations in CT chemistry alter protein binding capacities among polymers from different plant species and developmental stages. Condensed tannins interact with proteins in feed, saliva and microbial cells, with microbial exoenzymes, and with endogenous proteins or other feed components, which alters digestive processes as compared with diets free of CT. Tannin levels exceeding 40 to 50 g kg(-1) DM in forages may reduce protein and DM digestibility of the forages by ruminants. At low to moderate levels, CT increase the quantity of dietary protein, especially essential amino acids, flowing to the small intestine. Unlike alfalfa, legumes that contain CT do not cause bloat. Dietary CT may provide a means to beneficially manipulate protein digestion and/or prevent pasture bloat in ruminants. Research efforts are also currently being directed to genetically modify alfalfa to de-repress its CT biosynthetic pathway, or to move genes encoding steps of this pathway into alfalfa from other legumes. The effects of CT in forage legumes on digestion in ruminants and the potential use of tannin-rich forages for preventing bloat in grazing systems are discussed.

********************

Seed bank dynamics: the role of fungal pathogens and climate change. Leishman, M.R.; Masters, G.J.; Clarke, I.P.; Brown, V.K. 2000. Functional Ecology. V 14:293-299.
1. One of the climate change scenarios predicted for the UK is warmer winters and additional summer rainfall, which may favour growth and survival of fungal pathogens. We tested several hypotheses on the fate of persistent seeds in the soil and the role of fungal pathogens under this predicted climate change. 2, We buried seed bags containing fungicide-treated and non-fungicide-treated seeds of four species with persistent seed banks (Convolvulus arvensis L., Lotus corniculatus L., Medicago lupulina L. and Rubus fruticosus L.) under control and simulated climate change (winter warming plus supplemented summer rain) conditions, and monitored seed survival over 1 to 2 years. 3. Fungicide treatment resulted in a significant increase in the percentage of intact seeds recovered for only two of the four species, M. lupulina and R. fruticosus. Seeds of M. lupulina that were treated with fungicide remained viable in the soil for longer than non-treated seeds. Thus, the effect of fungal pathogens on seed persistence in the soil appears to be species specific. 4. There was no significant effect of the simulated climate (winter warming plus supplemented summer rain) on seed persistence in the soil, for any of the four species. Neither was a significant climate x fungicide treatment interaction found for any of the four species. Thus, it does not appear that the conditions provided in the simulated climate plots favoured the growth and survival of fungal pathogens affecting the soil seed banks of the four species studied here. 5. The use of fungicides in manipulative experiments and the importance of field experiments that simulate predicted climate change are discussed.

********************

Plants from protoplasts isolated from a long-term root culture (Super Root) of Lotus corniculatus. Akashi, R.; Harris, S.; Hoffmann-Tsay, S.S.; Hoffmann, F. 2000. Journal of Plant Physiology. V 157:215-221.
In the legume bird's-foot trefoil (Lotus corniculatus L.), a super-growing root (super root) culture has been recently introduced. This system is unique because it allows continuous root cloning, somatic embryogenesis and mass regeneration of plants under entirely hormone-free culture conditions. Here we report the isolation and culture of protoplasts from this long-term root culture (more than three years old) and the regeneration of plants from super root-derived protoplasts. Treatment of pre-cultured super roots with an enzyme mixture containing 4.0% cellulase and 0.1% pectolyase in 0.25 mol/L mannitol/0.25 mol/L sorbitol plus 0.1 % CaCl2 led to the separation of the root tips from the rest of the roots and, within four hours, to the isolation of approximately 3.0x10(6) protoplasts per gram root tissue. Protoplasts were released almost entirely from the separated root-lips and cultured, embedded in small agarose disks, in a modified KM8P medium supplemented with 0.05 mg/L BAP, 0.1 mg/L 2,4-D and 0.5 mg/L NAA. After five to seven days, the first divisions were observed, and after four weeks micro calli of 0.5 to 1 mm could be recovered. Calli were placed on MS medium containing relatively high concentrations of BAP and NAA (both 1.5 mg/L) for four weeks, resulting in prolific shoot formation. Elongated shoots rooted easily on hormone-free medium, and plants could be established. Roots from regenerated plants and roots formed directly on protoplast-derived calli were used to establish new root cultures. These newly initiated cultures expressed all the super root qualities again, including prolific shoot regeneration upon transfer to light, indicating that the super-growing character is not lost through protoplast isolation and regeneration. The super root pathway of regeneration, from protoplasts to callus, roots, root culture and plants, allows the virtually unlimited mass regeneration of plants from root protoplasts. Regenerating super root protoplasts add an important component to tissue culture systems for legume/Rhizobium research. Furthermore, this is the first report on plant regeneration from protoplasts isolated from a true root culture rather than excised roots.

********************

Growth and water relations of Lotus creticus creticus plants as affected by salinity. Morales, M.A.; Alarcon, J.J.; Torrecillas, A.; Sanchez-Blanco, M.J. 2000. Biologia Plantarum. V 43:413-417.
Young plants of Lotus creticus creticus growing in a hydroponic culture were submitted to 0, 70 and 140 mM NaCl treatments for 28 d and the growth and ecophysiological characteristics of these plants have been studied. The growth of Lotus plants was not affected by salinity when applied for a short period (about 15 d); however, 140 mM NaCl induced a decrease in shoot RGR at the end of the treatment. The root growth was not decreased, even it was stimulated by 140 mM NaCl. The osmotic adjustment of Lotus plants at 70 and 140 mM NaCl maintained constant pressure potential, avoiding the visual wilting. For a similar leaf water potential, cuticular transpiration of salinized plants was lower than in control plants due to the salinity effect on the cuticle. Moreover, the presence of hairy leaves (60 and 160 trichomes per mm(2) in young acid adult leaves, respectively) allows keeping almost 81% of sprayed water and absorbing the 9% of the water retained, decreased the epidermal conductance to water vapour diffusion.

********************

Persistence of perennial cool-season grass and legume cultivars under continuous grazing by beef cattle. Brummer, E.C.; Moore, K.J. 2000. Agronomy Journal. V 92:466-471.
Persistence of highly productive forage species in pastures is essential to maximize economic returns from grazing livestock, However, most forage cultivars are neither developed nor evaluated under grazing. The objective of this study was to evaluate several cool-season forage species and cultivars to determine their tolerance to continuous grazing. Three grazing experiments were established in 1996 in central Iowa: (i) 20 cultivars and populations of alfalfa (Medicago sativa L.), (ii) 15 cultivars representing five cool-season legume species, and (iii) 25 cultivars and germplasms of six tool-season grass species. Beef cattle (Bos taurus) continuously grazed the experiments for about four months in 1997 and 1998. Alfalfa yield was measured in adjacent plots. Stand survival ratings were taken each year. Among the alfalfa entries, grazing-tolerant 'Alfagraze' showed high persistence but moderate yield. Several new alfalfa populations combined excellent grazing tolerance with yield equal to the best hay-type cultivar, Kura clover (Trifolium ambiguum Bieb.) and white clover (T. repens L.) persisted better than alfalfa, birdsfoot trefoil (Lotus corniculatus L.), and red clover (T. pratense L.), with no loss of stand after two grazing years. Orchardgrass (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Schreb.) persisted well, though considerable variation was present among orchardgrass cultivars after the second grazing year. Reed canarygrass (Phalaris arundinacea i,.) and smooth bromegrass (Bromus inermis Leyss.) stands were reduced to <10% after one grazing year. Although the severe, continuous grazing used in these experiments is not recommended, it clearly and quickly differentiates among species and cultivars for grazing tolerance.

********************

Binary legume-grass mixtures improve forage yield, quality, and seasonal distribution. Sleugh, B.; Moore, K.J.; George, J.R.; Brummer, E.C. 2000. Agronomy Journal. V 92:24-29.
Yield and forage quality of kura clover (Trifolium ambiguum Bieb.) and intermediate wheatgrass [Thinopyrum intermedium (Host.) Barkw. & D.R. Dewey] mixtures compared with commonly grown forages such as alfalfa (Medicago sativa L.) and smooth bromegrass (Bromus inermis Leyss.) have not been fully explored. Our objective was to evaluate the effects of alfalfa, birdsfoot trefoil (Lotus corniculatus L.), and kura clover grown in binary mixtures with orchardgrass (Dactylis glomerata L.), smooth bromegrass, and intermediate wheatgrass on seasonal distribution of forage yield and quality. Plots of each species in monoculture and binary legume-grass mixtures were established in a randomized complete block design in 1994 near Boone, IA. Yield was measured monthly during the 1995 and 1996 seasons. In vitro dry matter digestibility (IVDMD), neutral-detergent fiber (NDF), and crude protein (CP) concentrations were determined for each monoculture or mixture. Total yield was highest for monoculture alfalfa, alfalfa-intermediate wheatgrass, and alfalfa-smooth bromegrass with 13 400, 12 700, and 12 600 kg ha(-1) respectively in 1995, and 7500, 6800, and 6700 kg ha(-1) respectively, in 1996. Kura clover had the lowest NDF (357 g kg(-1)) and highest IVDMD (740 g kg(-1)) concentrations compared with other forages. Yield, CP, and IVDMD concentrations of monoculture grasses were lower than those of the legume-grass mixtures or of the monoculture legumes. Legumes improved the seasonal distribution of yield and forage quality by beig more productive at later harvests. Yield of alfalfa-intermediate wheatgrass was equal to or better than other alfalfa-grass mixtures and could make a valuable legume-grass alternative.

********************

Divergent selection for resistance to fusarium root rot in birdsfoot trefoil. Altier, N.A.; Ehlke, N.J.; Rebuffo, M. 2000. Crop Science. V 40:670-675.
Persistence of birdsfoot trefoil (Lotus corniculatus L.) is limited by the interaction of several factors including root and crown diseases caused by Fusarium oxysporum Schlecht. (Snyd. & Hans.). A greenhouse evaluation method was developed to screen and characterize birdsfoot trefoil germplasm for reaction to fusarium root rot. Plants were grown in 104-cell styrofoam seed starter trays. Roots were allowed to grow through the bottom of each cell into the soil in boxes below. Twelve weeks after seeding, roots were cut 6 cm below the crown and inoculated with a composite of F. oxysporum fungal isolates by spreading a layer of sand and inoculum across the box surface. Ten weeks later, plants were scored for percentage of internal rot (IR) in a transverse root section and length of vertical discoloration (VD) from the inoculation site. One cycle of bidirectional selection for reaction to F. oxysporum was conducted within the adapted cultivar San Gabriel. Plants scoring IR <5% and IR >30% were selected and intercrossed to produce resistant and susceptible Cycle 1 populations. The parental source population, resistant and susceptible Cycle 1 populations, and five Uruguayan and North American germplasms were characterized for fusarium root rot reaction. Mean disease severity varied among birdsfoot trefoil entries (IR range: 5.7-18.7%, VD range: 1.2-3.8 cm). The resistant Cycle 1 population had lower IR and VD scores than the parental population, San Gabriel. Phenotypic mass selection was effective in changing the frequency of root rot reaction, indicating that breeding for resistance to fusarium root rot has the potential to increase the persistence of birdsfoot trefoil in the field.

********************

Methods for evaluating birdsfoot trefoil for susceptibility to foliar and shoot blight caused by Rhizoctonia spp. English, J.T.; Beuselinck, P.R. 2000. Crop Science. V 40:841-843.
Production of birdsfoot trefoil (Lotus corniculatus L,.) is limited in humid, temperate regions by foliar and shoot blight caused by Rhizoctonia species. The objective of this study was to develop methods for quantifying blight symptoms on 14 plant introductions and three cultivars of birdsfoot trefoil. Susceptibility was evaluated in the greenhouse on the basis of shoot lesion formation and blight of leaves and apical meristems. On the basis of these symptoms, no entry of this limited collection of birdsfoot trefoil was completely resistant to infection. However, 4 d after inoculation, shoot lesion length differed significantly among entries. Additionally, lesion lengths varied between experiments in relation to environmental conditions. In contrast to shoot lesion length, foliar blight and the time to blight of apical meristems did not vary significantly among entries in either experiment. Shoot lesion development limits foliage production and survival under field conditions and should be considered an important factor in further screening of birdsfoot trefoil for disease resistance.

********************

Birdsfoot trefoil seed production: II. Plant-water status on reproductive development and seed yield. Garcia-Diaz, C.A.; Steiner, J.J. 2000. Crop Science. V 40:449-456.
Forage legume seed crop responses to water stress differ for each species, so a single optimal water management strategy is not applicable. The objectives of this study were to determine the effects of irrigation timing and replenishment amount on birdsfoot trefoil (Lotus corniculatus L.) reproduction and seed yield in the Willamette Valley of western Oregon, USA. Six treatments varying in water depletion percentage and replenishment amount were applied in 1994 and 1995 on a Woodburn silt loam soil (fine-silty, mixed, mesic Aquultic Argixeroll) near Corvallis. In 1996, only a low stress (LS) that met the weekly crop evapotranspirative demand and a non-irrigated control (C) treatment were investigated. In the first year of production, maintaining plants under low-stress conditions sustained flowering longer than with limited or no irrigation. Flowering was not affected by irrigation in the subsequent two production years. Total above-ground phytomass was correlated with the amount of irrigation water (r = 0.92). The C and all single application treatments had greater seed yields (SY) than the LS treatment in 1994. In 1995, all single application treatments had greater SY than the LS treatment. There was no difference between LS and C in 1995 and 1996. Umbel density and the number of seeds per pod were the primary determinants of total seed yield (r = 0.77 and 0.92, respectively). Optimal total seed production was achieved without supplemental irrigation under the humid temperate marine climatic conditions found in western Oregon.

********************

Birdsfoot trefoil seed production: III. Seed shatter and optimal harvest time. Garcia-Diaz, C.A.; Steiner, J.J. 2000. Crop Science. V 40:457-462.
Seed shattering is a major problem in birdsfoot trefoil (Lotus corniculatus L.) seed production and limited information is available describing the effects of agronomic practices on shatter losses. The objectives of this research were to: (i) quantify the effects of soil-water availability on seed shatter and (ii) determine optimal harvest time on the basis of a heat unit method to minimize birdsfoot trefoil seed losses under western Oregon climatic conditions. Six treatments varying In water depletion percentage and replenishment amount were applied in 1994 and 1995 and two treatments in 1996 on a Woodburn silt loam soil (fine-silty, mixed, mesic Aquultic Argixeroll) near Corvallis, OR. The total amount of shattered seeds was correlated with total harvested seed yield (r = 0.93), Crop water stress index (CWSI) was inversely related to the percentage of seeds shattered (r = - 0.76), Increasing amounts of applied water increased the potential of seed field shattered (r = 0.65). Seed shatter losses fluctuated during the late-reproductive period, but were not influenced by irrigation or fluctuating climatic conditions, A total of 109 heat units (approximately 11 d), which were determined on the basis of a 10 degrees C base temperature, were accumulated from the time of initial pod dehiscence until rapid seed shattering. The average seed yield losses due to shattering was 3 to 5.3 kg ha(=) d(=1). The non-irrigated control treatment generally produced more seeds than irrigated treatments. it is, thus, best not to irrigate birdsfoot trefoil grown for seed in western Oregon because increasing amounts of irrigation water increased seed shattering.

********************

Analysis of expressed sequence tags of flower buds in Lotus japonicus. Endo, M.; Kokubun, T.; Takahata, Y.; Higashitani, A.; Tabata, S.; Watanabe, M. 2000. DNA Research. V 7:213-216.
In order to study gene expression in a reproductive organ, we constructed a cDNA library of mature flower buds in Lotus japonicus, and characterized expressed sequence tags (ESTs) of 842 clones randomly selected. The EST sequences were clustered into 718 non-redundant groups. From BLAST and FASTA search analyses of both protein and DNA databases, 58.5% of the EST groups showed significant sequence similarities to known genes. Several genes encoding these EST clones were identified as pollen-specific genes, such as pectin methylesterase, ascorbate oxidase, and polygalacturonase, and as homologous genes involved in pollen-pistil interaction. Comparison of these EST sequences with those derived from the whole plant of L. japonicus, revealed that 64.8% of EST sequences from the flower buds were not found in EST sequences of the whole plant. Taken together, the EST data from flower buds generated in this study is useful in dissecting gene expression in floral organ of L. japonicus.

********************

Generation of 7137 non-redundant expressed sequence tags from a legume, Lotus japonicus. Asamizu, E.; Nakamura, Y.; Sato, S.; Tabata, S. 2000. DNA Research. V 7:127-130.
For comprehensive analysis of genes expressed in a model legume, Lotus japonicus, a total of 22,983 5' end expressed sequence tags (ESTs) were accumulated from normalized and size-selected cDNA libraries constructed from young (2 weeks old) plants. The EST sequences were clustered into 7137 non-redundant groups. Similarity search against public non-redundant protein database indicated that 3302 groups showed similarity to genes of known function, 1143 groups to hypothetical genes, and 2692 were novel sequences. Homologues of 5 nodule-specific genes which have been reported in other legume species were contained in the collected ESTs, suggesting that the EST source generated in this study will become a useful tool for identification of genes related to legume-specific biological processes. The sequence data of individual ESTs are available at the web site: http://www.kazusa.or.jp/en/plant/lotus/EST/.

********************

Voluntary intake, digestibility and nitrogen utilization by sheep fed ensiled forage legumes. Fraser, M.D.; Fychan, R.; Jones, R. 2000. Grass and Forage Science. V 55:271-279.
An experiment was conducted to compare the nutritive value of a range of ensiled forage legumes. Silages were prc paled from late second-cut lotus (Lotus corniculatus), first-cut sainfoin (Onobrychis viciifolia) and both early and late second-cut red clover (Trifolium pratense) and lucerne (Medicago sativa). Each experimental silage was offered to six Suffolk-cross wether lambs, aged 10 months, housed in metabolism crates. Voluntary intakes of dry matter ranged from 71 to 81 g kg(-1) livewcight(0.75) d(-1) Voluntary intakes were similar on the lotus, sainfoin and late-cut red clover silages, hut the voluntary intake on the lotus silage was significantly higher than that on the lucerne silages and early-cut red clover silage. Digestibility of organic matter in the dry matter was highest for the lotus silage (0.650), and lowest fur the sainfoin silage (0.527). Although most of the N in thc sainfoin silage appeared to be in an indigestible form, N digestibility was approximately 0.70 for the other legume silages. The highest loss of N in urine, 0.75 of N intake, was recorded fur lambs offered the lucerne silage. Differences in N intake, N loss in faeces and N loss in urine led to statistically significant differences in the amount of N retained, with the highest and lowest N balances recorded for the lotus (16 g N d-1) and sainfoin (-2 g N d(-1)) silages respectively. The results confirm that the-se high protein forages have high intake potential. While low N digestibility appears to limit the nutritional value of sainfoin, further research could formulate feeding strategies that improve the efficiency with which the protein from red clover, lucerne and lotus is utilized.

********************

The Lotus japonicus LjSym4 gene is required for the successful symbiotic infection of root epidermal cells. Bonfante, P.; Genre, A.; Faccio, A.; Martini, I.; Schauser, L.; Stougaard, J.; Webb, J.; Parniske, M. 2000. Molecular Plant-Microbe Interactions. V 13:1109-1120.
The role of the Lotus japonicus LjSym4 gene during the symbiotic interaction with Mesorhizobium loti and arbuscular mycorrhizal (AM) fungi was analyzed with two mutant alleles conferring phenotypes of different strength. Ljsym4-1 and Ljsym4-2 mutants do not form nodules with M. loti. Normal root hair curling and infection threads are not observed, while a nodC-dependent deformation of root hair tips indicates that nodulation factors are still perceived by Ljsym4 mutants. Fungal infection attempts on the mutants generally abort within the epidermis, but Ljsym4-1 mutants allow rare, successful, infection events, leading to delayed arbuscule formation. On roots of mutants homozygous for the Ljsym4-2 allele, arbuscule formation was never observed upon inoculation with either of the two AM fungi, Glomus intraradices or Gigaspora margarita. The strategy of epidermal penetration by G. margarita was identical for Ljsym4-2 mutants and the parental line, with appressoria, hyphae growing between two epidermal cells, penetration of epidermal cells through their anticlinal wall. These observations define a novel, genetically controlled step in AM colonization. Although rhizobia penetrate the tip of root hairs and AM fungi access an entry site near the base of epidermal cells, the LjSym4 gene is necessary for the appropriate response of this cell type to both microsymbionts. We propose that LjSym4 is required for the initiation or coordinated expression of the host plant cell's accommodation program, allowing the passage of both microsymbionts through the epidermis layer.

********************

Structural and expression analysis of uricase mRNA from Lotus japonicus. Takane, K.; Tajima, S.; Kouchi, H. 2000. Molecular Plant-Microbe Interactions. V 13:1156-1160.
Uricase (nodulin-35) cDNA, LjUr, was isolated from nodules of a model legume, Lotus japonicus. LjUr expression was most abundant in nodules, although it was detected in nonsymbiotic tissues as well, particularly in roots. Expression in nodules was detected in uninfected cells, nodule parenchyma, and, more intensely, in vascular bundles. Phylogenetic analysis of uricase sequences from various legumes indicated that uricases of amide- and ureide-transporting legumes form two distinct clades. LjUr is in the cluster of amide-transport legumes even though L. japonicus bears determinate nodules.

********************

Identification of high-affinity binding sites for the hepta-beta-glucoside elicitor in membranes of the model legumes Medicago truncatula and Lotus japonicus. Cote, F.; Roberts, K.A.; Hahn, M.G. 2000. Planta. V 211:596-605.
Previous studies have led to the identification and characterization of specific, high-affinity binding sites for a hepta-beta-glucoside elicitor in soybean. A survey of plant species for elicitor-binding activity reveals that among the plants tested, the hepta-beta-glucoside elicitor is only recognized by plants belonging to the legume family. We have characterized in detail the glucan elicitor-binding site in the model legume Medicago truncatula Gaertn., and partially characterized the site in Lotus japonicus. These sites have characteristics that ale very similar to the one in soybean, with dissociation constants of 4.7 and 8.9 nM respectively. The elicitor-binding sites from both plants are stable during solubilization with non-ionic alkylglycoside detergents. However. differences are observed in the abundance of the binding sites and their selectivity towards structurally related analogues of the hepta-beta-glucoside elicitor. Our results suggest that similar, but perhaps not identical. binding sites for the hepta-beta-glucoside elicitor exist, in diverse legumes, but not in plants outside of the legume family.

********************

Vestigial corolla in flowers of birdsfoot trefoil. Beuselinck, P.R.; McGraw, R.L. 2000. Crop Science. V 40:964-967.
A naturally occurring floral mutant is infrequently observed in some populations of birdsfoot trefoil (Lotus corniculatus L). The petals of mutant flowers are folded inward and do not extend fully, producing a vestigial corolla (vc), while other floral parts remain normal. The style extrudes through a gap between the rudimentary keel and the folded standard, consequently, the stigma and style extend beyond the corolla and are exposed, The spatial separation between stigma and anthers could facilitate hand-pollination as it eliminates the need for emasculation. The objective of this study was to determine the fertility of L. corniculatus genotypes expressing vc floral characters. Sixteen genotypes of L. corniculatus expressing the re phenotype were collected from field grown populations. Pollen from vc genotypes was compared with pollen from genotypes of the germplasm MU-81 used as controls. All vc genotypes produced some pollen that appeared normal, although the quantity of such pollen was variable among the vc genotypes. Mean pollen germination among sc genotypes was 22%, compared with 50% for MU-81. Only five of 16 vc genotypes produced pods when crossed to genotypes of MU-81 and both pod and seed set were less than in control crosses. Normal and abnormal ovules were observed in ovaries of vc genotypes and the reduced fertility may have resulted from smaller, incompletely developed ovules. Unidirectional reversion of the vc genotypes, from abnormal to normal flower morphology, was common. Using the vc mutant to eliminate the need for emasculation in hand-pollination programs depends on its fertility. The combination of phenotypic instability and reduced fertility make the vc mutant less desirable for use in breeding programs.

********************

Registration of ARS-1221 big trefoil germplasm. Steiner, J.J.; Beuselinck, P.R. 2000. Crop Science. V 40:1204-1205.

********************

Registration of ARS-1207 narrow leaf trefoil germplasm. Steiner, J.J.; Beuselinck, P.R. 2000. Crop Science. V 40:1205.

Consequences of long-term feeding with condensed tannins on sheep parasitised with Trichostrongylus colubriformis. Athanasiadou, S.; Kyriazakis, I.; Jackson, F.; Coop, R.L. 2000. International Journal for Parasitology. V 30:1025-1033.
Naive wethers were used to investigate the long-term effects of dietary condensed tannins from Quebracho extract, during an intestinal parasitic infection in sheep. Sheep were allocated to eight groups; seven groups were daily infected with 3000 L-3 Trichostrongylus colubriformis for 10 weeks and the eighth group was the uninfected control. The 10-week experiment was divided into two periods; Period 1 (P-1, week 1-5) corresponded to high worm establishment and acquisition of immunity, whereas Period 2 (P-2, week 6-10) to the established worm population and expression of host immunity. Three experimental foods with similar composition were formulated: Q0, Q3 and Q6. Their difference was in the content of Quebracho extract which was 0, 30 and 60 g per kg fresh matter, respectively. All foods were offered at an allowance of 3.5% of sheep liveweight. During PI, parasitised sheep were offered one of the three experimental foods and during P-2 they either remained on the same food or changed food according to the design (P-1-P-2): Q0-Q0, Q0-Q3, Q0-Q6, Q3-Q0, Q3-Q3, Q6-Q0, Q6-Q6. Control sheep were offered the allowance of Q0 throughout Sheep that consumed Q3 and Q6 reduced their faecal egg counts (FEC) compared to sheep offered Q0, during both periods (P < 0.05). No differences were observed in the FEC between sheep offered Q3 and Q6. The changeover from Q0 in P-1 to either Q3 or Q6 during PZ, was-accompanied by a reduction in FEC (P < 0.05), whereas an increase in FEC was observed when food changed from Q3 or Q6 to Q0 (P < 0.05) Worm burdens and fecundity at the end of the experiment were reduced in sheep offered foods Q3 and Q6 compared to sheep offered Q0. A significant decrease in liveweight gain and in food conversion efficiency of parasitised sheep offered Q3 and Q6 compared to sheep offered Q0, was observed in PI (P < 0.05) but not in P-2. By the end of the experiment control sheep had achieved higher liveweight and converted food more efficiently than parasitised sheep (P < 0.05). In conclusion, evidence for a long-term effect of Quebracho extract, during both the initial establishment and on the established T. colubriformis population in sheep, was provided by the present study. It is suggested that the effect observed was a direct anthelmintic effect of the condensed tannins included in sheep diets.

********************

Water uptake by roots: effects of water deficit. Steudle, E. 2000. Journal of Experimental Botany. V 51:1531-1542.
The variable hydraulic conductivity of roots (Lp(r)) is explained in terms of a composite transport model. It is shown how the complex, composite anatomical structure of roots results in a composite transport of both water and solutes. In the model, the parallel apoplastic and cell-to-cell (symplastic and transcellular) pathways play an important role as well as the different tissues and structures arranged in series within the root cylinder (epidermis, exodermis, cortex, endodermis, stelar parenchyma). The roles of Casparian bands and suberin lamellae in the root's endo- and exodermis are discussed. Depending on the developmental state of these apoplastic barriers, the overall hydraulic resistance of roots is either more evenly distributed across the root cylinder (young unstressed roots) or is concentrated in certain layers (exo- and endodermis in older stressed roots). The reason for the variability of root Lp(r), is that hydraulic forces cause a dominating apoplastic flow of water around protoplasts, even in the endodermis and exodermis. In the absence of transpiration, water flow is osmotic in nature which causes a high resistance as water passes across many membranes on its passage across the root cylinder. The model allows for a high capability of roots to take up water in the presence of high rates of transpiration (high demands for water from the shoot). By contrast, the hydraulic conductance is low, when transpiration is switched off. Overall, this results in a non-linear relationship between water flow and forces (gradients of hydrostatic and osmotic pressure) which is otherwise hard to explain. The model allows for special root characteristics such as a high hydraulic conductivity (water permeability) in the presence of a low permeability of nutrient ions once taken up into the stele by active processes. Low root reflection coefficients are in line with the idea of some apoplastic bypasses for water within the root cylinder. According to the composite transport model, the switch from the hydraulic to the osmotic mode is purely physical. In the presence of heavily suberized roots, the apoplastic component of water flow may be too small. Under these conditions, a regulation of radial water flow by water channels dominates. Since water channels are under metabolic control, this component represents an 'active' element of regulation. Composite transport allows for an optimization of the water balance of the shoot in addition to the well-known phenomena involved in the regulation of water flow (gas exchange) across stomata. The model is employed to explain the responses of plants to water deficit and other stresses. During water deficit, the cohesion-tension mechanism of the ascent of sap in the xylem plays an important role. Results are summarized which prove the validity of the coehesion/tension theory. Effects of the stress hormone abscisic acid (ABA) are presented. They show that there is an apoplastic component of the flow of ABA in the root which contributes to the ABA signal in the xylem. On the other hand, (+)-cis-trans-ABA specifically affects both the cell level (water channel activity) and water flow driven by gradients in osmotic pressure at the root level which is in agreement with the composite transport model. Hydraulic water flow in the presence of gradients in hydrostatic pressure remains unchanged. The results agree with the composite transport model and resemble earlier findings of high salinity obtained for the cell (Lp) and root (Lp,) level. They are in line with known effects of nutrient deprivation on root Lp, and the diurnal rhythm of root Lp, recently found in roots of Lotus.

********************

Molecular mechanisms in root nodule development. Crespi, M.; Galvez, S. 2000. J. Plant Growth Regul. Vol. 19:155-166.
Under nitrogen-limiting conditions, bacteria from the family Rhizobiaceae establish a symbiosis with leguminous plants to form nitrogen-fixing root nodules. These organs require a coordinated control of the spatiotemporal expression of plant and bacterial genes during morphogenesis. Both plant and bacterial signals are involved in this regulation in the plant host. Plant genes induced during nodule development, the so-called nodulin genes, have been extensively characterized. Products of several of these genes show homologies to known regulators of signal transduction pathways in other plant or animal systems. Initial functional analysis of the molecular mechanisms implicated in nodulation have been undertaken using model legumes. Insertion mutagenesis and transgenic technologies to modify nodulin gene expression, as well as pharmacologic approaches, have been used to analyze molecular mechanisms involved in morphologic responses induced by the bacterial symbiont in the plant. G protein-mediated transduction mechanisms have been implicated, and the nin transcription factor appears to be required for early steps in nodule development. ENOD40, a gene coding for an RNA that contains only short ORFs, seems to be closely tied to nodule primordium formation. In addition, a vascular-associated Kruppel-like transcription factor and small Rab type G-proteins affect bacteroid differentiation and the function of the nitrogen-fixing zone. These initial results presage a wealth of information that will be obtained from the application of genomic approaches to legumes.

********************

The effect of condensed tannins in Lotus corniculatus upon reproductive efficiency and wool production in sheep during late summer and autumn. Min, B.R.; McNabb, W.C.; Barry, T.N.; Kemp, P.D.; Waghorn, G.C.; McDonald, M.F. 1999. Journal of agricultural science. v. 132:323-334.
A grazing experiment, conducted for 55 days (from 4 March to 29 April) in the late summer/autumn of 1997, at Massey University, Palmerston North, New Zealand, compared the reproductive efficiency and wool growth of ewes grazing Lotus corniculatus (birdsfoot trefoil) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) dominant pasture (pasture). Half the ewes grazing each forage were given daily oral polyethylene glycol (PEG: molecular weight 3500) supplementation to inactivate the condensed tannins (CT) in lotus. A rotational grazing system with 200 mixed age ewes (54(.)2 +/- 0(.)88 kg/ewe; 50 ewes/treatment) was used. The effect of forage species and PEG supplementation upon voluntary feed intake (VFI), concentration of plasma metabolites, reproductive efficiency, wool production and wool characteristics was measured during two synchronized oestrous cycles. The ewes were restricted to maintenance feeding for the first 12 days of each oestrous cycle and then increased to ad libitum for the 6 days prior to and including ovulation. Lotus contained 17 g total CT/kg dry matter (DM) in the diet selected. There were only trace amounts of total CT in pasture. In vitro organic matter digestibility (OMD) was higher for lotus (0(.)82 v. 0(.)74) than for pasture, whilst lotus contained less nitrogen (N; 37(.)8 v.44(.)5 g/kg OM). Mean ovulation rates (OR) for CT-acting and PEG sheep grazing pasture and lotus were respectively 1(.)33 v. 1(.)35 and 1(.)78 v. 1(.)56, with corresponding lambing percentages being 1(.)36 v. 1(.)36 and 1(.)70 v. 1(.)42. Fecundity (number of corpora lutea/ewe ovulating) was greater for ewes grazing lotus than pasture (P < 0(.)01), and tended to be greater for CT-acting than for PEG sheep grazing lotus (P = 0(.)06). In unsupplemented sheep, ewes grazing lotus had increased plasma concentrations of branched chain amino acids (BCAA; 57%) and essential amino acids (EAA; 52%) compared to ewes grazing pasture. In ewes grazing pasture, PEG administration had no effect on plasma concentrations of urea and free amino acids, VFI, reproductive efficiency and wool production. However, in sheep grazing lotus, plasma concentrations of urea were significantly lower and concentrations of most amino acids were significantly higher for CT-acting than for PEG supplemented ewes (CT not acting); there was no difference in VFI between these two groups. Compared to ewes grazing pasture, ewes grazing lotus had similar VFI but produced more wool with longer staples and thicker fibre diameter, with there being no effect of PEG supplementation. It was concluded that feeding lotus increased the efficiency of both reproduction and wool production without an increase in VFI, and that a possible cause was the action of CT in increasing plasma EAA and especially BCAA concentration.

********************

Development of N2-fixing nodules on the wetland legume Lotus uliginosus exposed to conditions of flooding. James, E.K.; Sprent, J.I. 1999. New phytologist. v. 142:219-231.

********************

Germination and seedling growth at low temperature: comparison of Lotus species and effects of selection and seed source in L. pedunculatus Cav. Kelman, W.M.; Forrester, R.I. 1999. Australian journal of agricultural research. v. 50:969-975.

********************

Kura clover establishment methods. Seguin, P.; Sheaffer, C.C.; Ehlke, N.J.; Becker, R.L. 1999. Journal of production agriculture. v. 12:483-487.
Kura clover (Trifolium ambiguum M.B.) is a rhizomatous legume that produces high quality forage and has exceptional persistence. However, slow establishment has limited its use. Our objective was to evaluate the effect of alternative establishment methods on Kura clover forage and seed production. At Rosemount, MN, we compared the effect of an oat (Avena sativa L.) companion crop harvested for forage; a birdsfoot trefoil (Lotus corniculatus L.) companion crop seeded with or without preplant herbicide application (trifluralin); and solo-seeding with or without a preplant herbicide application (trifluralin) on Kura clover yield and plant populations. At Roseau, MN, we determined the effect of solo-seeding with or without preplant herbicide (trifluralin), or with a flax (Linum usitatissimum L.) or a wheat (Triticum aestivum L.) companion crop on Kura clover forage and seed yield in the year following seeding. Kura clover forage production in the seeding and post-seeding years was maximized when solo-seeded with a preplant herbicide; however, results were variable across years. Kura clover forage yields in the seeding year were very low (< 400 lb/acre) for all treatments. An oat companion crop increased total weed-free forage yields in the seeding year, but reduced by 46% Kura clover yields in the seeding and post seeding years compared with solo-seeding with herbicide. A birdsfoot trefoil companion crop produced similar or lower Kura clover yields in the seeding and post-seeding year as solo-seeding with herbicide but similar or greater total forage yields. Seed production only occurred for solo-seeding with a preplant herbicide. Solo-seeding with herbicide is the most reliable establishment method for Kura clover forage and seed production; however, Kura clover establishment remains challenging.

********************

Presence of 3-nitropropionic acid, in widely distributed pasture legumes in Britain. Simpson, D.J.; Wainwright, S.J.; Hipkin, C.R. 1999. The Veterinary record : journal of the British Veterinary Association. v. 145:169-171.

********************

Establishment, growth and persistence of greater lotus (Lotus uliginosus) at six sites in eastern Australia. Blumenthal, M.J.; Bowman, A.M.; Cole, A.; Jones, R.M.; Kelman, W.M.; Launders, T.E.; Nicol, H.I. 1999. Australian journal of experimental agriculture. v. 39:819-827.

********************

Evaluation of the population dynamics of the forage legume Lotus corniculatus using matrix population models. Emery, K.M.; Beuselinck, P.; English, J.T. 1999. The New phytologist. v. 144:549-560.

********************

Seed-to-seed allelopathic effects between two invaders of burned Pampa grasslands. Laterra, P.; Bazzalo, M.E. 1999. Weed research. v. 39:297-308.

********************

T-DNA tagging of nodulation- and root-related genes in Lotus japonicus: expression patterns and potential for promoter trapping and insertional mutagenesis. Martirani, L.; Stiller, J.; Mirabella, R.; Alfano, F.; Lamberti, A.; Radutoiu, S.E.; Iaccarino, M.; Gresshoff, P.M.; Chiurazzi, M. 1999. Molecular plant-microbe interactions. v. 12:275-284.
High-efficiency transformation of the autogamous diploid legume Lotus japonicus by means of Agrobacterium rhizogenes was used to develop plant lines expressing a promoter-less gusA gene in a nodulation- or lateral root-associated manner. The approach exploits the putatively preferential integration of T-DNA into actively transcribed regions, thereby providing an enrichment for gene tagging events associated with the quickly assayable activation of a gusA promoter-less construct. Taking advantage of this enrichment and selection strategy, a T-DNA tagging program was initiated and screening for beta-glucuronidase (GUS) activity was performed on root clones isolated after transformation with a gusA-promoter-less binary vector. The aim of this approach is the identification of genes involved in nodule formation induced by Mesorhizobium loti, lateral root organogenesis, and the eventual isolation of corresponding mutants. A large collection (220) of GUS-positive transformants showing a variety of expression patterns in different regions of roots and nodules was obtained; a preliminary molecular characterization of these plants is presented.

********************

Effect of competition on the responses of grasses and legumes to elevated atmospheric CO2 along a nitrogen gradient: differences between isolated plants, monocultures and multi-species mixtures. Navas, M.L.; Garnier, E.; Austin, M.P.; Gifford, R.M. 1999. New phytologist. v. 143:323-331.

********************

A Nod factor-binding lectin is a member of a distinct class of apyrases that may be unique to the legumes. Roberts, N.J.; Brigham, J.; Wu, B.; Murphy, J.B.; Volpin, H.; Philipps, D.A.; Etzler, M.E. 1999. Molecular & general genetics. v. 262:261-267.

********************

Genetic nomenclature guidelines for the model legume Lotus japonicus. Stougaard, J.; Szczyglowski, K.; De Bruijn, F.J.; Parniske, M. 1999. Trends in plant science. v.4:300-301.

********************

Flooding tolerance in five populations of Lotus glaber Mill. (Syn. Lotus tenuis Waldst. et. Kit.). Vignolio, O.R.; Fernandez, O.N.; Maceira, N.O. 1999. Australian journal of agricultural research. v. 50:555-559.

********************

Forage legumes as living mulches for trees in agroforestry practices--preliminary results. lley, J.L.; Garrett, H.E.; McGraw, R.L.; Dwyer, J.P.; Blanche, C.A. 1998/1999. Agroforestry systems an international journal. v. 44:281-291.

********************

Responses of Lotus corniculatus to environmental change. 2. Effect of elevated CO2, temperature and drought on tissue digestion in relation to condensed tannin and carbohydrate accumulation. Carter, E.B.; Theodorou, M.K.; Morris, P. 1999. Journal of the science of food and agriculture. v. 79:1431-1440.
Clonal plants of three genotypes of Lotus corniculatus (cv Leo) were grown in eight controlled environments under combinations of two temperature regimes, two CO(2) concentrations and two watering regimes. Condensed tannins (proanthocyanidins), in-vitro digestibility, initial rates of gas evolution (as an indicator of the initial rates of fermentation of the substrate), volatile fatty acid evolution, and non-structural carbohydrate (NSC) levels were determined in leaves, stems and roots at full flowering. Under control conditions (average midsummer conditions in the United Kingdom) the total condensed tannin content of leaves varied six-fold between genotypes but condensed tannin contents in stems and roots were similar. Condensed tannin levels were significantly increased in leaves and stems of all three genotypes by doubling the CO(2) concentration while raising the temperature towards the optimum for growth significantly reduced condensed tannin levels. Drought stress significantly reduced condensed tannin levels in leaves and, particularly, in roots. Nutritive value was inversely related to condensed tannin levels in leaves and a negative relationship was observed between condensed tannin concentrations of more than 25-30 g kg(-1) dry matter and the initial rates of gas evolution when subjected to in-vitro fermentation with rumen micro-organisms. In leaves, digestibility was significantly increased by drought and by increasing temperature but reduced by high CO(2). In stems, digestibility was significantly increased by drought, but not significantly affected by increasing temperature, or by high CO(2) alone. In roots, digestibility was significantly increased by drought, and decreased by increasing temperature or CO(2). Increasing the growth temperature towards optimum growth reduced the content of NSC in all tissues with the greatest changes occurring in root tissue. Doubling the CO(2) concentration increased NSC levels in leaves and stems with starch content more than doubled under high CO(2) while, in roots, increased levels were only observed in combination with drought stress. There was a linear correlation between condensed tannin concentration and total NSC that was positive for leaves, neutral for stems and negative for roots. The relationship between carbohydrate levels and rates of gas production was negative for leaves and positive for stem and roots.

********************

The final step of pantothenate biosynthesis in higher plants: cloning and characterization of pantothenate synthetase from Lotus japonicus and Oryza sativum (rice). Genschel, U.; Powell, C.A.; Abell, C.; Smith, A.G. 1999. Biochemical journal. v. 341:669-678.

********************

Birdsfoot trefoil seed production. I. Crop-water requirements and response to irrigation. Garcia-Diaz, C.A.; Steiner, J.J. 1999. Crop science. v. 39:775-783.
Forage legume seed crop reproduction can be modified by regulating soil-water availability. However, responses to water stress differ for each species, so a single optimal water management strategy is not available for all crops. The objectives of this research were to determine the crop-water requirements and the optimal water management conditions for birdsfoot trefoil (Lotus corniculatus L.) when grown for seed production under humid temperate marine climatic conditions of western Oregon, USA. The experiment was conducted on a Woodburn silt loam soil (fine-silty, mixed, mesic Aquultic Argixeroll) near Corvallis. Four single-application treatments varying in water depletion percentage (30 and 60% of field capacity) and replenishment amount (50 and 100% of amount depleted) were applied in 1994 and 1995. A low-stress treatment (LS) that received two to three applications per week of the amount depleted since the last application and a non-irrigated control were also investigated in 1994, 1995, and 1996. Increasing amounts of applied water resulted in increased seasonal crop evapotranspiration (ET(c)) with plants grown under low-stress having the greatest ET(c) and non-irrigated control plants the least (r = 0.91). The fraction of available soil water used by non-irrigated plants was greatest and the LS treatment the least of all treatments. For non-irrigated conditions, the crop-water requirement ranged from 240 to 255 mm. Soil-water conditions favorable for high vegetative development were opposite of the conditions for optimal seed yield water-use efficiency. Unlike other forage legume seed crops, birdsfoot trefoil grown under these conditions required minimal or no supplemental irrigation to achieve maximal seed yield.

********************

Lotus japonicus nodulates and fixes nitrogen with the broad host range Rhizobium sp. NGR234. Hussain, A.K.M.A.; Jiang, Q.; Broughton, W.J.; Gresshoff, P.M. 1999. Plant and cell physiology. v. 40:894-899.
Lotus japonicus possesses major advantages as a model legume for the study of plant-microbe interactions. The relative absence of genetic information on its normal microbial partner (i.e., Mesorhizobium loti) could limit its utility in research. Here we show for the first time that the broad host range Rhizobium strain NGR234 nodulates and fixes nitrogen in symbiosis with Lotus japonicus ecotypes "Gifu" and "Funakura". We demonstrate that bacterial mutants deficient in nodulation or nitrogen fixation possess the expected phenotype with L. japonicus. Nodulation of L. japonicus was sensitive to nitrate. Vermiculite was an efficient synthetic growth substrate, allowing axenic growth in Magenta jars. The genetic analysis of the Lotus japonicus-Mesorhizobium interaction should be accelerated through the use of this well-defined microsymbiont.

********************

Degradation of atrazine, metolachlor, and pendimethalin in pesticide-contaminated soils: effects of aged residues on soil respiration and plant survival. Anhalt, J.C.; Arthur, E.L.; Anderson, T.A.; Coats, J.R. 2000. Journal of environmental science and health. Part B: Pesticides, food contaminants, and agricultural wastes. v. B35:417-438.

********************

A cladistic analysis of the Old World species of Lotus L. (Fabaceae: Loteae). Arambarri, A.M. 2000. Canadian journal of botany. v. 78:351-360.

********************

Intensive grazing management of smooth bromegrass with or without alfalfa or birdsfoot trefoil: heifer performance and sward characteristics. Barker, J.M.; Buskirk, D.D.; Ritchie, H.D.; Pas.; Rust, S.R.; Leep, R.H.; Barclay, D.J. 1999. Professional animal scientists. v. 15:130-135.

********************

Diurnal variations in hydraulic conductivity and root pressure can be correlated with the expression of putative aquaporins in the roots of Lotus japonicus. Henzler, T.; Waterhouse, R.N.; Smyth, A.J.; Carvajal, M.; Cooke, D.T.; Schaffner, A.R.; Steudle, E.; Clarkson, D.T. 1999. Planta. v. 210:50-60.
The hydraulic conductivity of excised roots (LP(r)) of the legume Lotus japonicus (Regel) K. Larsen grown in mist (aeroponic) and sand cultures. was found to vary over a 5-fold range during a day/night cycle. This behaviour was seen when Lp(r) was measured in roots exuding, either under root pressure (osmotic driving force), or under an applied hydrostatic pressure of 0.4 MPa which produced a rate of water flow similar to that in a transpiring plant. A similar daily pattern of variation was seen in plants grown in natural daylight or in controlled-environment rooms, in plants transpiring at ambient rates or at greatly reduced rates, and in plants grown in either aeroponic or sand culture. When detached root systems were connected to a root pressure probe, a marked diurnal variation was seen in the root pressure generated. After excision, this circadian rhythm continued for some days. The hydraulic conductivity of the plasma membrane of individual root cells was measured during the diurnal cycle using a cell pressure probe. Measurements were made on the first four cell layers of the cortex, but no evidence of any diurnal fluctuation could be found. It was concluded that the conductance of membranes of endodermal and stelar cells may be responsible for the observed diurnal rhythm in root LP(r). When mRNAs from roots were probed with cDNA from the Arabidopsis aquaporin AthPIP1a gene, an abundant transcript was found to vary in abundance diurnally under high-stringency conditions. The pattern of fluctuations resembled closely the diurnal pattern of variation in root LP(r). The plasma membranes of root cells were found to contain an abundant hydrophobic protein with a molecular weight of about 31 kDa which cross-reacted strongly to an antibody raised against the evolutionarily conserved N-terminal amino acid sequence of AthPIP1a.

********************

Does root glutamine synthetase control plant biomass production in Lotus japonicus L.? Limami, A.; Phillipson, B.; Ameziane, R.; Pernollet, N.; Jiang, Q.; Roy, R.; Deleens, E.; Chaumont-Bonnet, M.; Gresshoff, P.M.; Hirel, B. 1999. Planta. v. 209:495-502.
To investigate the contribution of root cytosolic glutamine synthetase (GS) activity in plant biomass production, two different approaches were conducted using the model legume Lotus japonicus. In the first series of experiments, it was found that overexpressing GS activity in roots of transgenic plants leads to a decrease in plant biomass production. Using (15)N labelling it was shown that this decrease is likely to be due to a lower nitrate uptake accompanied by a redistribution to the shoots of the newly absorbed nitrogen which cannot be reduced due to the lack of nitrate reductase activity in this organ. In the second series of experiments, the relationship between plant growth and root GS activity was analysed using a series of recombinant inbred lines issued from the crossing of two different Lotus ecotypes, Gifu and Funakura. It was confirmed that a negative relationship exists between root GS expression and plant biomass production in both the two parental lines and their progeny. Statistical analysis allowed it to be estimated that at least 13% of plant growth variation can be accounted for by variation in GS activity.

********************

Soil water dynamics and growth of perennial pasture species for dryland salinity control. Lolicato, S.J. 2000. Australian journal of experimental agriculture. v. 37-45.

********************

Polyphenols and agriculture: beneficial effects of proanthocyanidins in forages. Aerts, R.J. ; Barry, T.N.; McNabb, W.C. 1999. Agriculture, ecosystems & environment. v. 75:1-12.
Proanthocyanidins (PA), also known as condensed tannins, belong to the oldest of plant secondary metabolites. These compounds are widespread in woody plants, but are also found in certain forages. Proanthocyanidins can exert effects in organisms because of their ability to complex with proteins. Forages containing moderate concentrations of PA (2-4% DM) can exert beneficial effects on protein metabolism in sheep, slowing degradation of dietary protein to ammonia by rumen micro-organisms and increasing protein outflow from the rumen, thus increasing absorption of amino acids in the small intestine of the animal. This was shown to result in increases in lactation, wool growth and liveweight gain, without changing voluntary feed intake. Dietary PA can also contribute to improved animal health by reducing the detrimental effects of internal parasites in sheep and the risk of bloat in cattle. In contrast, high dietary PA concentrations (6-12% DM) depress voluntary feed intake, digestive efficiency and animal productivity. Temperate forages containing PA, such as Lotus corniculatus and L. pedunculatus, will not persist in intensive grazing systems if continuously grazed (i.e. set stocked), especially in mixtures with perennial ryegrass and white clover and need to be grown as pure species and rotationally grazed. Nevertheless, inputs of these 'special purpose' forages can increase sustainability and productivity in intensive grazing systems through increasing the efficiency of animal production, reducing urinary nitrogen (N) excretion and reducing chemical inputs as anthelmintics and as detergents used to control rumen bloat in cattle. Proanthocyanidins are derived from the flavonoid biosynthesis pathway, and knowledge is rapidly increasing about the molecular control of PA biosynthesis. These recent investigations may ultimately enable the expression by genetic engineering of increased levels of PA in the leaves of agriculturally important forage plants such as white clover and perennial rye grass, which will withstand continuous defoliation under grazing and currently contain only trace amounts of PA. This could potentially lead to the widespread use of PA in temperate grazing systems. Further consideration, should now be given to long-term adaptations in the animal, and to ecological effects on the soil ecosystem by PA and their degradation products excreted in animal faeces. More information is required in particular on the effects of PA on soil nitrification, ammonia volatilisation from soil, and nitrogen levels in the groundwater.

********************

Pasture renovation and grazing management impacts on cool-season grass pastures. Cuomo, G.J.; Johnson, D.G.; Forcella, F.; Rudstrom, M.V.; Lemme, G.D.; Martin, N.P. 1999. Journal of production agriculture. v. 12:564-569.
Legumes have been shown to increase production in cool-season grass pastures. However, they are included in relatively few acres of pasture. A split plot experiment with six replications was conducted to evaluate the impact of pasture renovation and grazing management on forage production and species composition of cool-season grass pastures. Grazing management main plots were grazed to leave low (2-4 in.), medium (4-6 in.), or high (6-8 in.) residue levels. Main plots were intensively grazed (50 000-70 000 lb of cows per acre) five or six times per grazing season by lactating Holstein cows. Subplot pasture renovation treatments were (i) an untreated check, or sprayed with glyphosate and interseeded with (ii) alfalfa (Medicago sativa L.), (iii) red clover (Trifolium pratense L.) and birdsfoot trefoil (Lotus corniculatus L.), or (iv) "graziers mix" (a mixture of legumes and grasses). Areas that were grazed to leave low residue level produced less forage mass (4.7 ton/acre) than areas grazed to medium (5.4 ton/acre) or high (5.5 ton/acre) residue levels. When averaged across years and grazing management treatments, renovated areas produced 1.8 ton/acre (46%) more forage than the control. Of interseeded species, alfalfa, red clover, and orchardgrass persisted through the study (more than 25% of the dry matter in at least one of the pasture renovation treatments). By June 1998, thistle (Carduus and Cirsium spp.) was present in all treatments. Fewer thistle was present in areas that were grazed to leave low residue (10 sq yd) than high residue (18 sq yd) and in renovated areas (9 sq yd) than the control (22 sq yd). The additional forage produced as a result of pasture renovation cost from $8.07/ton to $12.81/ton. This study indicates that pasture renovation can be a valuable tool for increasing forage production in cool-season grass pastures.

********************

Water-selective and multifunctional aquaporins from Lotus japonicus nodules. Guenther, J.F.; Roberts, D.M. 2000. Planta. v. 210:741-748.
By using reverse transcriptase-polymerase chain reaction, two cDNAs were isolated that encode major intrinsic membrane proteins (MIPs) that are expressed in nitrogen-fixing root nodules of Lotus japonicus. Lotus intrinsic membrane protein 1 (LIMP 1) is expressed at high levels in both nodule and root tissues and shows highest sequence similarity to members of the tonoplast intrinsic protein (TIP) subfamily of plant MIPs. Functional analysis of LIMP 1 by expression in Xenopus laevis oocytes show that it is a water-specific aquaporin. In contrast, LIMP 2 shows the highest sequence similarity to soybean nodulin 26 (67.8% amino acid sequence identity). LIMP 2 is also a nodulin, showing expression only in mature nitrogen fixing nodules of L. japonicus. LIMP 2 is a multifunctional aquaglyceroporin, and displays the ability to flux both water as well as glycerol upon expression in Xenopus oocytes. Additionally, the carboxyl terminal region of LIMP 2 has a conserved phosphorylation motif that is phosphorylated by a calmodulin-like domain protein kinase. Overall, the data show that L. japonicus nodules contain two structurally and functionally distinct MIP proteins: one (LIMP 2) which appears to be the nodulin 26 ortholog of L. japonicus and another (LIMP 1) which appears to be a member of the TIP subfamily.

********************

Streptothricin resistance as a novel selectable marker for transgenic plant cells. Jelenska, J. ; Tietze, E.; Tempe, J.; Brevet, J. 2000. Plant cell reports. v. 19:298-303.
Streptothricins are known as antimicrobial agents produced by Streptomyces spp. Bacterial resistance to streptothricin is mediated by specific enzymes exhibiting an acetyltransferase activity which renders the drug non-toxic for bacteria. The nucleotide sequence of several streptothricin resistance genes from bacteria have been described. Certain cells of eukaryotic parasites (such as Ustilago maydis or Leishmania spp.) are sensitive to streptothricin and the introduction of the bacterial resistance gene sat2 renders them resistant. We show that numerous species of plants are sensitive to low concentrations of streptothricin. Moreover, introduction of the bacterial resistance gene sat3 under the control of the 35S cauliflower mosaic virus promoter protects these cells from the toxic action of streptothricin. Therefore, sat3-mediated streptothricin resistance appears to be a promising selective marker for genetic manipulation of plant cells.

********************

Invasion and reproduction of Pratylenchus penetrans in birdsfoot trefoil cultivars. Kimpinski, J. ; Papadopoulos, Y.A.; Christie, B.R.; McRae, K.B.; Gallant, C.E. 1999. Phytoprotection. v. 80:179-184.

********************

New trefoils give breeders more options. Stelljes, K.B. 2000. Agricultural research. v. 48:22.

********************

Lupine leghemoglobin I: expression in transgenic Lotus and tobacco tissues. Strozycki, P.M. ; Karlowski, W.M.; Dessaux, Y.; Petit, A.; Legocki, A.B. 2000. Molecular & general genetics. v. 263:173-182.

********************

Root hydraulic conductance: diurnal aquaporin expression and the effects of nutrient stress. Clarkson, D.T.; Carvajal, M.; Henzler, T.; Waterhouse, R.N.; Smyth, A.J.; Cooke, D.T.; Steudle, E. 2000. Journal of experimental botany. v. 51:61-70.
It has been shown that N-, P- and S-deficiencies result in major reductions of root hydraulic conductivity (Lp(r)) which may lead to lowered stomatal conductance, but the relationship between the two conductance changes is not understood. In a variety of species, Lp(r) decreases in the early stages of NO3-, H2PO4(2-) and SO4(2-) deprivation. These effects can be reversed in 4-24 h after the deficient nutrient is re-supplied. Diurnal fluctuations of root Lp(r) have also been found in some species, and an example of this is given for Lotus japonicus. In nutrient-sufficient wheat plants, root Lp(r) is extremely sensitive to brief treatments with HgCl2; these effects are completely reversible when Hg is removed. The low values of Lp(r) in N- or P-deprived roots of wheat are not affected by Hg treatments. The properties of plasma membrane (PM) vesicles from wheat roots are also affected by NO3- -deprivation of the intact plants. The osmotic permeability of vesicles from N-deprived roots is much lower than that of roots adequately supplied with NO3-, and is insensitive to Hg treatment. In roots of L. japonicus, gene transcripts are found which have a strong homology to those encoding the PIP1 and PIP2 aquaporins of Arabidopsis. There is a very marked diurnal cycle in the abundance of mRNAs of aquaporin gene homologues in roots of L. japonicus. The maxima and minima appear to anticipate the diurnal fluctuations in Lp(r) by 2-4 h. The temporal similarity between the cycles of the abundance of the mRNAs and root Lp(r) is most striking. The aquaporin encoded by AtPIP1 is known to have its water permeation blocked by Hg binding. The lack of Hg-sensitivity in roots and PMs from N-deprived roots provides circumstantial evidence that lowered root Lp(r) may be due to a decrease in either the activity of water channels or their density in the PM. It is concluded that roots are capable, by means completely unknown, of monitoring the nutrient content of the solution in the root apoplasm and of initiating responses that anticipate by hours or days any metabolic disturbances caused by nutrient deficiencies. It is the incoming nutrient supply that is registered as deficient, not the plant's nutrient status. At some point, close to the initiation of these responses, changes in water channel activity may be involved, but the manner in which monitoring of nutrient stress is transduced into an hydraulic response is also unknown.

********************

Seed bank dynamics: the role of fungal pathogens and climate change. Leishman, M.R. ; Masters, G.J.; Clarke, I.P.; Brown, V.K. 2000. Functional ecology. v. 14:293-299.

********************

Transplantation of the subshrub Lotus scoparius: testing the home-site advantage hypothesis. Montalvo, A.M. ; Ellstrand, N.C. 2000. Conservation biology. v. 14:1034-1045.

Back to the Table of contents