1. Introduction: instructions to contributors notes from the editor
2. Lotus Activities: reports and abstracts
3. Recent Lotus Literature
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| O Genetics | O Breeding | O Taxonomy | O Physiology |
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P. R. Beuselinck, USDA-ARS
University of Missouri
207 Waters Hall
Columbia, MO 65211 USA
FAX 573-882-1467
Purpose:
The Lotus Newsletter consists of informal
communications of research information on Lotus spp. Reports
of any phase of research on Lotus breeding, genetics, taxonomy,
management, utilization or physiology are welcome. Your biographic
sketches and information about your research objectives, approaches,
and progress including titles of your publications are encouraged.
Seed requests and news items are accepted.
This is the 27th year of publication for the
Lotus Newsletter. Now is the time
to consider contributing to the 28th volume of the Lotus
Newsletter. Contributions generally are compiled without
editing.
1. Prepare your contribution using any IBM (MS-DOS) or Macintosh word processing program. Then you have two options:
a. submit the file on 3.5 " (90 mm) disk accompanied by a printed copy of the contribution. Identify which program you used. OR
b. submit the file to my e-mail address (pbeuselinck@plantsci.missouri.edu)
and send me a hardcopy by FAX to 573-882-1467, or by regular mail.
1. Single space typewritten text on white 8.5" x 11" (21.5 cm x 27.5 cm) paper. Double space between paragraphs and tables. Do not number pages.
2. Leave a minimum of 3/4" (1.9 cm) on the left and bottom of each page.
3. On the first page of each contribution, indicate state or country, title of report, and name(s) of contributor(s).
4. Send your contributions by December 31,
1996 to:
Lotus Newsletter
Dr. P. R. Beuselinck, USDA-ARS
Plant Genetics Research Unit
207 Waters Hall
University of Missouri
Columbia, MO 65211 U.S.A.
E-mail: pbeuselinck@plantsci.missouri.edu
FAX 573-882-1467
The expense of publishing the Lotus Newsletter has been partially covered by unrestricted research support. I will continue to strive for financial support of the Lotus Newsletter to provide you with an unencumbered communication resource. Please note my comments about an internet version of the Lotus Newsletter below.
Many thanks to you who respond to my requests for information about your Lotus research. Your contributions to the Lotus Newsletter help generate a better perspective of the international research and management on the many species of Lotus.
Requests for distribution the Lotus Newsletter to university or research libraries are accepted. If you have a library that needs a copy for your research group or center please notify me. Please note my comments about an internet version of the Lotus Newsletter below.
There is a limited supply of back issues available. Supplies of most volumes have been depleted, but requests will be handled on a first-come first-served basis.
This was the last issue of the Lotus Newsletter to be printed in a hardcopy form. The cost of printing and mailing has become quite expensive. You should be able to go the Lotus Newsletter homepage and print a copy for yourself or you simply access the homepage and read the volume of your choice without filling your bookshelf. My goal is to work my way back through all the volumes until they are all in electronic format.
From the homepage you should be able to access the current volume or past volumes. The current volume for the year will be a compilation of all Lotus news and articles received between January 1 through December 31.
The internet address for the Lotus Newsletter is: http://www.plantsci.missouri.edu/lnl
If you have not filled-out and sent in a questionnaire in the last two years please complete one. If you know of others interested in the Lotus Newsletter have them submit a questionnaire and they'll be added to the mailing list.
The illustration on the cover is of Lotus conjugatus L. has again been graciously provided by Ana Arambarri (Argentina) . The Lotus illustration is the 4th in a series of illustrations that started with Volume 23.
Justification
Birdsfoot trefoil (Lotus corniculatus) possesses characteristics
that should make it well suited for use in high elevation mountain
meadows. However, its potential benefits in that environment have
not been demonstrated through research. Therefore, very few producers
ever consider birdsfoot trefoil when selecting a legume for seeding.
Most producers cut their high elevation meadows (6,000 - 10,000 ft.) once for hay and then graze any regrowth off in the fall. Birdsfoot trefoil fits this production scheme because first cutting yields are high (i.e. comparable to alfalfa) and the regrowth can be safely grazed due to birdsfoot trefoil's non-bloating characteristic. Birdsfoot trefoil also maintains good forage quality over an extended period of time because of its indeterminate growth habit and better leaf retention capabilities compared to many other legumes. This trait has positive implications for producers that cannot realistically harvest all their hay at peak quality due to constraints such as time, labor, or weather.
The addition of legumes to grass dominated meadows can increase
both the quantity and quality of forage produced. Legumes such
as red clover (Trifolium pratense), alsike clover (Trifolium
hybridum), and alfalfa (Medicago sativa) have been
successfully interseeded into mountain meadows in the past. Birdsfoot
trefoil seedlings lack vigor and do not compete well with existing
vegetation which often makes establishment difficult. The objectives
of this study were to evaluate varieties of birdsfoot trefoil
potentially adapted for use in mountain meadows and to determine
the impact of different seedbed preparations on establishment
success of the varieties.
Study Area
This study was established on the Trampe Ranch approximately 6.5
miles north of Gunnison, Colorado at 7800 ft. elevation. The soil
is classified as a Fola cobbly sandy loam (loamy-skeletal, mixed
Borollic Camborthid). Species present at the site include: common
meadow foxtail (Alopecurus pratensis), timothy (Phleum
pratense), smooth brome (Bromus inermis), Kentucky
bluegrass (Poa pratensis), red clover, alsike clover, dandelion
(Taraxacum officinale), herbaceous cinquefoil (Potentilla
pulcherrima), and alfalfa. The alfalfa was from an old interseeding
and consisted of widely scattered plants. Annual precipitation
is evenly distributed and averages 10.5 inches at Gunnison. Snowfall
averages 54 inches per year. Meadows used for forage production
are flood irrigated. The average frost-free growing season is
63 days, however, freezing temperatures can occur on any day of
the year.
Methods and Materials
Birdsfoot trefoil was seeded on May 24, 1994 at the rate of 6 lbs pure live seed/ac. Varieties evaluated were: 'Carroll', 'Norcen', 'Leo', 'Tretana', and 'Empire'. An entry of 'Empire' that was coated with clay containing the appropriate Rhizobium bacteria for root nodulation and the fungicide Apron® was also evaluated and was designated as 'Empire-C'. All other varieties were inoculated just prior to seeding with standard inoculant (Nitragin Company). Plots were seeded with a John Deere Powr-till® drill (Model 1550, 8 ft.). An unseeded plot was left as a control.
The different varieties were seeded into 3 types of seedbeds. The first consisted of seeding directly into the existing vegetation with no effort to suppress competition. The existing vegetation was approximately 4-6 inches tall at the time of seeding. This treatment was considered the control. The second seedbed treatment consisted of suppressing the existing vegetation with Roundup® sprayed 2 weeks prior to seeding at the rate of 1.5 qts/ac. Although Roundup® is supposed to kill all plants that it comes in contact with, it generally only suppresses the more vigorous perennial grasses allowing the seedlings to become established. The third seedbed treatment consisted of tilling with a tractor-mounted rototiller to a depth of about 1 inch. The objective of this treatment was to eliminate or reduce shallow-rooted species such as Kentucky bluegrass and set back the deeper-rooted, desirable perennial grasses giving the seedlings time to become established.
Experimental design was a split-block with 3 replications. Plot size for each variety/seeding method combination was 10' x 24'. Each block measured 72' x 80'. The entire study area was fertilized with 80 lbs/ac of P2O5 just prior to seeding using triple superphosphate (0-45-0).
The study area was flood irrigated under the management of the
landowner. Harvest of plots was timed to coincide with the landowner's
normal haying which occurred on August 3 in 1995. Plots were harvested
with a New Holland mower/conditioner (9 ft., 3 in. header) which
left the forage in a windrow. The center 20 ft. of each windrow
was collected and weighed to estimate production. Two grab samples
were collected per plot. The first was used to determine moisture
content and overall hay quality. The second was separated into
components of alfalfa, birdsfoot trefoil, clover, forbs, and grass
to determine hay composition. Forage quality of individual components
was also analyzed. Crude protein and invitro dry matter digestibility
were analyzed as measures of forage quality. Production and quality
estimates will be gathered for at least one more year. Persistence
will be monitored over time.
Results
Interseeding birdsfoot trefoil into existing mountain meadow vegetation increased total forage yield an average of 650 lbs/ac compared to the unseeded control (Table 1). The variety 'Empire-C' that was established using coated seed was the only one that did not significantly increase total yield above the control. For some unknown reason, the seed coating inhibited establishment of this variety instead of enhancing it. The 'Empire-C' variety contributed only 4% to total production while the other varieties contributed between 15 and 22%. The relationship between the amount of birdsfoot trefoil in the hay and total yield was strong (r = 0.97). Plots seeded to the 'Norcen' variety produced the highest total yield at just over 2 tons/ac and had the highest average contribution from birdsfoot trefoil at 22%.
Averaged across varieties, birdsfoot trefoil increased crude protein content of the hay 2.3 percentage points compared to the control (Table 2). Crude protein content of the hay was lowest from plots seeded with the 'Empire-C' variety and highest from plots seeded with either the 'Leo' or 'Norcen' varieties. As with production, this trend was related to the amount of birdsfoot trefoil in the hay (r = 0.94). Digestibility of the hay was not affected by any of the birdsfoot trefoil varieties (Table 2).
Total forage yield was not affected by either the spray or tillage seedbed preparations (Table 3). Contribution of birdsfoot trefoil to total yield was 3 times higher from plots sprayed with Roundup® and about 2 times higher from tilled plots compared to the control. This result emphasizes the need to suppress the existing vegetation in some manner prior to seeding to improve establishment success of birdsfoot trefoil. However, there were some tradeoffs associated with the different suppression methods evaluated in this study. The tillage treatment increased grass composition compared to the spray and control treatments and decreased clover composition compared to the control (Table 3). The spray treatment also decreased clover composition compared to the control.
The changes in hay composition (Table 3) due to interseeding and suppression of the existing vegetation affected both crude protein content and digestibility of the hay (Table 4). An increase in grass and decrease in clover composition led to a reduction in both crude protein content and digestibility of the hay produced from the tillage plots compared to the control. Digestibility of hay from the sprayed plots was reduced about 3 percentage points compared to the control, possibly in response to reduced clover composition. Crude protein content of hay from the sprayed plots was not affected. The contribution of crude protein from birdsfoot trefoil probably offset any loss associated with decreased clover composition.
No significant differences in crude protein content or digestibility
were measured among the birdsfoot trefoil varieties (Table 5).
Crude protein content of birdsfoot trefoil averaged 17.3% which
was comparable to clover (Table 6). These 2 components were higher
in crude protein compared to alfalfa, grass, or forbs. Birdsfoot
trefoil was also the most digestible (67.2%) compared to the other
hay components (Table 6). Crude protein content and digestibility
of alfalfa were lower than expected because of the large, robust
growth form of the plants that were present. As density of alfalfa
declines over time, the remaining plants compensate by producing
stemmier growth that is generally higher in fiber (i.e. less digestible)
and lower in crude protein.
Summary
Birdsfoot trefoil that was interseeded into a mountain meadow
increased both the quantity and quality of forage produced in
the first production year. Differences among the varieties tested
were generally small. Suppression of the existing vegetation improved
establishment success. Plots sprayed with Roundup®
prior to seeding had the highest contribution of birdsfoot trefoil
to total production. Although these results from the first production
year appear promising, persistence of the different varieties
needs to be documented before birdsfoot trefoil can be commonly
recommended for seeding in mountain meadows.
Table 1. Effect of interseeding various varieties of birdsfoot trefoil on production and composition of mountain meadow hay. Samples were taken August 3, 1995. | ||||||
|
1Variety means were averaged across seeding methods. 2Means within columns followed by the same letter are not significantly different (P>0.05). | ||||||
Table 2. Effect of interseeding various varieties of birdsfoot trefoil on crude protein concentration and invitro dry matter digestibility of mountain meadow hay. Samples were taken August 3, 1995. | ||
|
1Variety means were averaged across seeding methods. 2Means within columns followed by the same letter are not significantly different (P>0.05). | ||
| Table 3. Effect of method of seeding (i.e. vegetation suppression method) birdsfoot trefoil on production and composition of mountain meadow hay. Samples were taken August 3, 1995. | ||||||
| -----------------------------------%---------------------------------- | ||||||
|
1Seeding method means were averaged across birdsfoot trefoil varieties. 2Means within columns followed by the same letter are not significantly different (P>0.05). | ||||||
Table 4. Effect of method of seeding (i.e. vegetation suppression method) birdsfoot trefoil on crude protein concentration and invitro dry matter digestibility of mountain meadow hay. Samples were taken August 3, 1995. | ||
|
1Seeding method means were averaged across birdsfoot trefoil varieties. 2Means within columns followed by the same letter are not significantly different (P>0.05). | ||
Table 5. Crude protein concentration and invitro dry matter digestibility of various birdsfoot trefoil varieties that were interseeded into a mountain meadow. Samples were taken August 3, 1995. | ||
|
1Varieties were composited across seeding methods. 2Means within columns followed by the same letter are not significantly different (P>0.05). | ||
Table 6. Crude protein concentration and invitro dry matter digestibility of various components of mountain meadow hay following interseeding of birdsfoot trefoil. Samples were taken August 3, 1995. | ||
|
1Varieties were composited or averaged across seeding methods. 2Means within columns followed by the same letter are not significantly different (P>0.05). | ||
ABSTRACT
Seed development and maturation at different stages of pod development
were studied Lotus corniculatus. Pods were classified into
4 different stages of development using morphological characters
such as colour and size. The effect on seed quality of three different
harvesting procedures at each stage of development was studied.
The number of normal seedlings and hard seed increased with stage
of development. Direct combining resulted in the lowest germination
potential whilst highest germination potential was obtained after
threshing seed from dried plants. Collecting pods and drying them
artificially showed post harvest maturation mainly by means of
hardseedness.
INTRODUCTION
The genus Lotus belongs to the subfamily Papilionatae (Wheeler
and Hill, 1957). It consists of a diverse group of annual and
perennial species widely distributed throughout the world (Callen,
1959).Lotus corniculatus, a perennial forage legume is
utilised in several countries in different parts of the world
(Seaney and Henson, 1970: Robinson, 1934: Orsi, 1953: Panikar,
1949: Gardner and Elliot (1945). This species has advantages due
to its forage quality and ability to tolerate low phosphorous
levels in soil and drought (Formoso, 1983). However lack of sufficient
seed yield has prevented its spread (Anderson, 1955: McGraw and
Beuselinck, 1983: Buckovic, 1952: Metcalfe et al, 1957). The gap
between the theoretical and actual seed yield is enormous (Seaney
and Henson, 1970). Lack of proper guides to determine the best
moment for harvesting have been mentioned by Pieroni (1992) and
this situation may lead to loss of seeds because of dehiscence
of pods or because of damage to seed if harvest is too early.
Several authors have studied the development of seeds of forage
legume from defined points early in the process of maturation
(Pieroni, 1992: Anderson, 1955: Hare and Lucas, 1984 ). The variability
of environment in different parts of the world, seasonal variation
in weather conditions and differences in populations mean that
it is difficult to make generalisations and practical recommendations
for crop management from these studies as the timing of maturation
may change. The objectives of the present work were to relate
the physiological development of seeds and seed quality to recognisable
morphological stages of pod development and to relate this to
harvesting treatment.
MATERIALS AND METHODS:
Field experiments were carried out at Terrington St. Clements,
Norfolk, England (52o 45' N: 0o15' W) during
July and August 1995. Laboratory tests were carried out at The
Official Seed Testing Station for Scotland, East Craigs, Edinburgh.
A 0.8 hectare crop of Lotus corniculatus was sown in 1991,
at a seed rate of 3.5 kg of seed per hectare at 45 cm between
furrows. Paraquat® and Linacil®
were applied during spring for weed control. The crop was grown
from wild populations collected in the British isles to produce
seed for natural habitat reconstruction. Experiments on reserve
accumulation: Pods were collected at each stage of development
in five replications taken from five random sites marked in the
field. The stages of development were defined as follows:1- Purple-green
pod colour, shorter than 2 cm.2- Green pod colour , longer than
2 cm and thicker than 1 mm, green seed.3- Yellow pod, turning
to light brown in colour, green- light brown seed.4- Dry, brown
pod colour, brown seed. After collection, pods were put in air-water
proof plastic bags, and stored at -20 oC prior to laboratory
studies. Laboratory studies involved opening the pods and removing
four sets of 50 seeds from each replicate at each stage of development.
The sub samples were weighed and dried in oven following ISTA
rules for moisture content (Seed Science and Technology, 1993)
. The following indices were calculated for each stage of development:
-1000 seed weight at harvest moisture content;- Moisture content
at harvest;- 1000 seed weight of dried seed.
Experiments on post harvest maturation: After pollination and
during the different stages of seed development, five replicates
of 200 pods were harvested from each of the sites described above
in three different ways as follows: Treatment 1 (t1)- Direct harvest
and threshing with a commercial combine, a HEGE 125b, with the
cylinder speed set at 1043 rpm and with cylinder-concave set as
small as possible (less than 0.5 cm). Treatment 2 (t2)- Picking
pods from the plants, drying and threshing them after drying as
in t1. Treatment 3 (t3)- Cutting entire plants and drying them.
Seeds were threshed after drying as above. These different harvesting
methods were applied at all the stages of development described
above, with the exception of the first one, where the seeds were
not physically big enough to be threshed by a combine. For all
the treatments, seed, pods or plants were dried on trays inside
a green house for at least one week. Plant material in the trays
was covered with paper to avoid direct exposure to sun. The average
temperature reached was 25oC with a maximum of 38oC
and a minimum of 12oC. The relative humidity of the
air varied between 40% and 60% Germination tests: Germination
tests were carried out according to ISTA rules (Seed Science and
Technology, 1993). Four replications of 100 seeds were counted
for each stage of development and harvesting treatment. The seed
was set to germinate on top of paper (Whatman 181) at 20/30oC.
The first count was made at 7 days and the second at 12 days.
Germinated, hard, abnormal, dead and fresh seeds were recorded.
RESULTS
All results were subject to analysis of variance using the GENSTAT program.
Reserve accumulation: Results are shown in table 1.
| Table 1: Development of moisture content, dry weight and fresh seed weight in Lotus corniculatus. | |||
Water content showed a decline through the stages of development
as shown in Table 1. The maximum fresh seed weight was reached
at stage 3, which represents a light yellow-brown pod. Dry seed
weight also changed drastically from stage 2 to stage 3, going
form 0.47 to 1.56 gr. per 1000 seeds.
Post harvest maturation.
Germination tests: The results from the germination test were classified into the following categories:
a) Normal seedling after 12 days.
b) Hard seeds: after 12 days at 20/30oC.
c) Normal seedlings plus abnormal seedlings
d)Total germination: This is the germination value of a seed lot
as assessed in an official germination test and includes normal
seedlings plus hard and fresh seeds. The results can be seen in
Figures 1 and 2 as the addition of normal, hard and fresh seeds.
A significant difference in amount of normal seedling and in amount
of hard seeds with P< 0.001 was found between stages of development
and harvesting treatment. Total germination value showed significant
differences between harvesting treatments, stages of development
and the interaction between treatments and stages (P< 0.01).Normal
plus abnormal seedling were scored to find any possible differential
mechanical damage in any treatment. No difference was found neither
in harvesting treatment nor stage of development for both crops.
The overall amount of abnormal seed recorded was 4.4% The proportion
of normal seedling, fresh seeds, hard seeds and total germination
are presented in Figures 1 and 2 according to stage of development
and harvesting treatment respectively.
Figure 1: Development of normal seedling, hard seed, fresh seed and total germination (addition) at different stages of development in Lotus corniculatus. Standard error bars are displayed for total germination value.
Figure 2: Amount of normal seedling, hard seed, fresh seed and
total germination (addition) at different harvesting treatment
in Lotus corniculatus. Standard error bars are displayed
for total germination value.
| Table 2: Total germination value in Lotus corniculatus at different combinations of harvesting treatment and stage of development. LSD = 6.5 for P=0.05 | |||
A significant effect of the harvesting treatment was found (P<
0.01). As shown in Figure 2, the direct combining treatment presented
the lowest germination rate, and both harvesting treatment 2 and
3 presented the highest quality without significant difference
between them. The harvesting treatment 3 showed some pods attacked
by a weevil that was identified as Apion loti. It was present
in plants picked from the field and attacked some pods during
the drying process decreasing the final quality of seed. That
could be the reason of a lower trend in the germination of seed
from dried plants. The higher germination rate in harvesting treatment
3 is mainly due to a higher amount of hard seeds (Figure 2), while
in the case of harvesting treatment 2 it is due to higher number
of normal seedling. A similar trend in development of germination
through the stages of pod development was found. Seed collected
from green pods showed an extremely low germination rate of 5.1%
, rising to 57.8% in seed from light yellow-brown pods and up
to 86.7 % in seed from brown pods. A significant difference was
also found in the interaction between harvesting treatment and
stage of development (P< 0.01). As shown in table 2 seed did
not tolerate direct combining during stage 3 but germination increased
dramatically at the same stage when seed were dried in pods or
with the entire plant. It also shows that after this stage and
treatment the germination value seems to reach a maximum between
80% and 90%.
DISCUSSION
According to Bewley and Black (1994) seed grows from a single
fertilised egg to a multicellular embryo by cell division and
differentiation. These events are marked by a period of rapid
increase in whole seed fresh weight and water content. A period
of rapid gain in dry weight then follows as a result of the synthesis
and deposition of stored reserves. The whole seed fresh weight
then remains relatively stable, although the seed loses water
as this is displaced by the accumulation of insoluble reserves
within the cells of storage tissues. The evolution of water content
shown in Table 1 is as expected in seeds during accumulation of
reserves. It seems that the very early stages of embryo development,
where amount of water content increases has been missed, which
means it happens before the first stage of development studied.
Bewley and Black (1994) also described that the decline in water
content of a developing seed slows as it approaches its maximum
dry weight. Finally as the seed undergoes maturation drying and
approaches the quiescent stage, when it may be shed from the plant,
there is a period of fresh weight loss accompanied by a rapid
decline in whole seed water content. The fact that there is a
sharp drop in water content going from 59% to 17% between the
last two stages seems to indicate that the desiccation occurs
in Lotus corniculatus at the transition from light yellow
to brown colour. Winch and MacDonald (1961) reported similar trend
for pods, in this case pod moisture content fell from 65% to 25%
when changing to light brown colour. A slightly higher moisture
content was reported by Anderson (1955) who stated that seed become
morphologically mature at the time pods have light brown colour,
having a moisture content of 35% to 40%.However, Seaney and Henson
(1970) suggest that seed become physiologically mature slightly
before pods change colour from green to light brown, which corresponds
in this case to the transition from stage 2 to stage 3. This might
indicate that seeds increase in fresh and dry matter content even
after physiological maturation as will be discussed ahead. Hare
and Lucas (1984) defined the development stages in Lotus
as: a) growing stage, b) food reserve accumulation stage and c)
the ripening stage, counting days from pollination to classify
these stages. In this experiment the evolution of dry matter content
and water content seems to indicate that the transition from stage
2 (green pods) to stage 3 (light yellow-brown) could be the beginning
of the food reserve accumulation stage, meanwhile the transition
from stage 3 to stage 4 (brown colour) could be the ripening one.
Post harvest maturation. As explained in results he higher germination
rate in the harvesting treatment 3 is mainly due to a higher amount
of hard seeds (Figure 2), while in the case of harvesting treatment
2 it is due to higher number of normal seedling. These results
also indicates that some post harvest maturation occurs in a different
way according to the drying environment. Bewley and Black (1994)
state that hardseedness is a common feature in the Leguminosae
family and is a kind of dormancy in which water entry is the limiting
factor for germination. They also state that the testa is generally
responsible for impeding water uptake through different structures
like the waxy cuticle, suberin or the thick-walled palisade cells.
Which of these anatomical structures are able to be changed during
the last stages of development or during different conditions
of drying has not been studied in this paper. It could be worth
more research in the matter since the understanding of this maturation
process can have implications in commercial seed production. The
trend in total germination value found at different stages of
development is as expected. However, Anderson (1955) working in
Iowa found higher germination rate during the green pod stage,
reaching 90 % with the sum of normal and hard seeds. It is not
known whether these differences in physiological maturity are
due to a genetic effect or due to a year difference. The small
drop in germination value in dried plants during the stage of
light yellow-brown pods could be explained by the Apion loti
attack. Hare and Lucas (1984) stated that Lotus pedunculatus
reached seed maturity at the time pods were light-brown yellowish
colour, at this stage seed had 65% moisture content. This stage
correspond with stage 3 in this experiment in which maximum germination
was still not reached even if seed had the same moisture content.
The results of the interaction between harvesting treatment and
stage of development also agree with Hare and Lucas (1984) who
recommended, as mentioned above, that mowing should start at light
brown colour stage. The differences shown in table 2, could be
important for commercial seed production and opens a field for
more research. If technology allowed a mechanised way of picking
pods from the field as early as the light-yellow brown pod stage
and drying artificially, harvesting could start in an earlier
stage of maturation, before dehiscence in field. If dehiscence
happens in-building it will not mean seed loses. During seed drying
in the harvesting treatment 2 and 3 no dehiscence of pods was
noticed in all the stages of development, but as mentioned above,
temperature reached an average of 25oC with variation
in relative humidity between 40% and 60%. Metcalfe et al. (1957)
mentioned that in the Midwest and Northeast U.S.A. seed losses
from pod shattering can be high when relative humidity drops below
40%. Similarly, Phillips and Keim (1968) found 35% of relative
humidity as the point where pods start a rapid dehiscence. Under
different climatic situations it is not sure that mowing the crop
and allowing it to dry in the field in an earlier stage would
have not dehiscence of pods.
BIBLIOGRAPHY:
Anderson S.R. (1955) Development of pods and seed of birdsfoot trefoil (Lotus corniculatus L.) as related to viability and to seed yield. Agronomy Journal 47: 483-487.
Bewley, J.D and Black, M. (1994) Seeds, Physiology of development and germination. Second edition. Plenum press, New York and London.
Buckovic, R.G. (1952). MSc. Thesis. Oregon State College, Corvallis, Oregon.
Callen, E.O. (1959) Studies of the genus Lotus. Canadian Journal of Botany 37: 157-165.
Formoso, F. (1983). Effect of defoliation in Lotus corniculatus. Lotus Newsletter 14: 3.
Gardner, C.A. and Elliot, H.G. (1945) West Australia Dep. Agr. J. 22: 358-360.
Hare, M.D. and Lucas, R.J. (1984). `Grassland Maku lotus (Lotus pedunculatus L.) seed production. Journal of Applied Seed Production 2: 58-64.
McGraw, R.L. and Beuselinck, P.R. (1983) Growth and seed yield characteristics of birdsfoot trefoil. Agronomy Journal 75: 443-446.
Metcalfe, D.S., Johnson, I.J. and Shaw, R.H. (1957). The relationship between pod dehiscence, relative humidity and moisture equilibrium in birdsfoot trefoil (Lotus corniculatus L.). Agronomy Journal 49: 130-134.
Orsi, S. (1953). Ann. Ente. Consor Interprov. Tosc. Sementa IV, 30.
Panikar, M.R.(1949). Indian Farming 10: 444-447.
Phillips, R.L. and Keim, W.F. (1968). Seed pod dehiscence in Lotus and interspecific hybridisation involving L. corniculatus L. Crop Science 8: 18-21.
Pieroni, S.J. (1992) Factors affecting seed yield and quality in temperate forage legumes. MSc Thesis. The Edinburgh School of Agriculture. University of Edinburgh.
Robinson, D.H. (1934) Birdsfoot trefoil in Agriculture. Empire J. Exp. Agr. 2: 274-283.
Seaney, R.R. and Henson, P.R. (1970). Birdsfoot trefoil. Advances in Agronomy 22: 119-157.
Seed Science and Technology (1993). V 21 Supplement Rules. International Rules for Seed testing.
Wheeler, W.A. and Hill, D.D. (1957). Seed formation and germination. In Grassland seeds. Eds. Wheeler, W.A. and Hill, D.D. London, D. Van Nostrand Company, Inc. pp 12-34.
Winch, J.E. and MacDonald, H.A. (1961). Flower pod and seed development relative to the timing of the seed harvest of Viking birdsfoot trefoil (Lotus corniculatus L.) Canadian Journal of Plant Science 41: 523-532.
1. Error in title of paper:
"A chromosome atlas and interspecific-intergenic index
for Lotus and Tetragonolobus (Fabaceae). Can. J.
Bot. 73: 1787-1809, 1995.
The correct title is:
A chromosome atlas and interspecific-intergeneric index
for Lotus and Tetragonolobus (Fabaceae).
2. Error in Table 1 in the list of species
studied:
"Genome relationships among Lotus species based on
random amplified polymorphic DNA (RAPD)" by L. P. Campos,
J. V. Raelson and W. F. Grant. Theor. Appl. Genet. 88: 417-422,
1994.
Table 1 lists the species and their chromosome
numbers studied. Accession B-557 listed as L. japonicus,
2n = 12, is incorrect. Accession B-557 is L. corniculatus
and the chromosome number is 2n = 24.
The greatest number of Lotus species are those with a basic
chromosome number of 7 (x = 7). Evolutionarily, these species
are considered to be the oldest. This group is followed by those
species which have a basic chromosome number of x = 6. Only a
single species has a basic chromosome number of 5 (L. glareosus).
Chromosome evolution in the genus is considered to be occurring
by means of a reduction in the basic number from x = 7 to x =
6 to x = 5, in a descending aneuploid series from an eight-chromosomed
ancestor of the tribe Galegeae (Senn, 1938). In the new world
only a reduction from x = 7 to x = 6 has taken place to date (Grant
1995). The question arises as to how this reduction in basic number
came about?
Chromosome measurements were made representing three European
species. A drawing of the chromosomes for Lotus strictus
(previously unpublished) was used for the 7-chromosome species.
Idiograms of the species L. glacialis (2n = 12) and L.
glareosus (2n = 10) are given in the paper of Fernandes and
Queiros (1980) and chromosome measurements were made from these
idiograms for these two species. From the measurements for all
three species, idiograms were drawn using the chromosome analysis
package CHROMPAC III (Green et al. 1984).
The data from the chromosome analyses are given in Table I. The
idiograms in Figures 1 and 2 are photocopied from Fernandes and
Queiros (1980). Figs. 3-5 represent the idiograms based on the
detailed measurements. Satellites were not included in the measurements
of chromosome length.
| Karyotype measurements for Lotus strictus, L. glacialis and L. glareosus | |||||||
| L. strictus | |||||||
| L. glacialis | |||||||
| L. glareosus | |||||||
*Ratio: Long arm (p) divided by short arm (q)
Type: M, chromosome with centromere in median position; SM, submedian;
ST, subterminal
Index: p/p+q
Fernandes and Queiros (1980) have shown 2 pairs of satellited chromosomes on the short arms in both L. glacialis (chromosomes B and D) and L. glareosus (chromosomes B and C) (Figs. 1-2). Although chromosome B is the longest chromosome in L. glacialis, the authors have drawn this chromosome as the second chromosome of the complement (reason unknown) rather than the first. In contrast, no satellited chromosomes were observed in any of the metaphases examined for L. strictus (Fig. 3).
The computer program drew the chromosomes in descending length.
Chromosome B in Fig. 1 becomes chromosome 1 in Fig. 4. As may
be seen from Figs. 3-5, chromosome 1, for all three species, is
morphologically similar with submedian to subterminal centromeres.
Fernandes and Queiros (1980) pointed out the similarity of chromosomes
C and D between L. glacialis and L. glareosus in
Figs. 1 and 2. They explained the reduction in chromosome number
from n = 6 to n = 5 on non-separation of the chromatids during
anaphase as they observed metaphase plates in root tip cells of
L. glacialis (2n = 12) with 13, 11, and 10 chromosomes,
in addition to the normal complement of 12. One restitution cell
would lack chromosome F (Fig. 1) giving rise to L. glareosus
(Fig. 2) lacking this chromosome. They considered chromosome F
to be largely heterochromatic and therefore dispensable which
lead to the development of a species with a reduced chromosome
number (L. glareosus). They also suggested that L. glareosus
was derived from L. glacialis by chromosome rearrangements,
but the actual mechanism and chromosomes involved were not specified.
Chromosomes 2 and 3 in L. strictus are also very similar
to those of chromosomes 3 and 4 in both L. glacialis and
L. glareosus. A translocation between chromosomes 4 and 5
in L. strictus would give a largely median chromosome as
is chromosome 5 in L. glacialis. The loss of chromosome
7 in L. strictus by being either genetically inert or through
missegregation in mitosis would reduce the number to 2n = 12.
Similarly, a translocation between chromosomes 1 and 2 in L.
glacialis could produce chromosome 2 in L. glareosus
. With the loss of chromosome 5, L. glareosus would result
with the reduced chromosome number. By the classical translocation
route, a reduction in basic chromosome number could have taken
place as hypothesized above. However, observations in which chromosome
irregularities occur in both root tips of somatic (Fernandes and
Queiros 1980; O'Donoughue and Grant 1989), and meiotic cells (Somaroo
and Grant 1972) and in Lotus hybrids (O'Donoughue and Grant
1988) with the subsequent development of plants with stable chromosome
numbers would be an alternate explanation for the initiation of
plants with a reduction in basic chromosome number.
Fernandes, A. and Queiros, M. 1980. Sur l'occurrence de la pseudo- reduction somatique chez Lotus glacialis (Boiss.) Pau. Bol. Soc. Brot., Ser. 2, 54: 133-152.
Grant, W. F. 1995. A chromosome atlas and interspecific - intergeneric index for Lotus and Tetragonolobus (Fabaceae). Can. J. Bot. 73: 1787-1809.
Green, D. M., Myers, P. Z. and Renya, D. L. 1984. CHROMPAC III: an improved package for microcomputer-assisted analysis of karyotypes. J. Hered. 75: 143.
O'Donoughue, L. S. and Grant, W. F. l988. New sources of indehiscence for birdsfoot trefoil (Lotus corniculatus, Fabaceae) produced by interspecific hybridization. Genome, 30: 459- 468.
O'Donoughue, L. S. and Grant, W. F. 1989. Chromosomal variation in Lotus alpinus (Fabaceae). Plant Species Biol. 4: 117-122.
Senn, H. A., 1938. Chromosome numbers in the Leguminosae. Bibliograph. Genet. 12: 175-336.
Somaroo, B. H. and Grant, W. F. 1972. Chromosome differentiation
in diploid species of Lotus (Leguminosae). Theor. Appl.
Genet. 42: 34-40.
INTRODUCTION
In the New World, the genus Lotus L. comprises approximately
40 species distributed from British Columbia to Mexico in North
America. Only one species is endemic to Chile in South America.
L. salsuginosus Greene and L. salsuginosus var.
brevivexillus Ottley; L. strigosus (Nuttall) Greene,
L. strigosus var. hirtellus (Greene) Ottley,
and L. strigosus var. tomentellus (Greene) Isely,
are found in California, Lower California and Mexico, and in the
islands west of Lower California.
Nuttall (1838) treated L. strigosus as belonging
to genus Hosackia Bentham ex Lindley. Greene (1890), examined
and included Nuttall's species into the genus Lotus L.
He named L. tomentellus to one species from Lower California.
Ottley (1923) considered L. salsuginosus and L. strigosus
into the subgenus Acmispon Rafinesque. Later, Ottley (1944)
segregated the species belonging to Acmispon into two sections.
The section Microlotus Benth. (6 species) containing L.
salsuginosus and its variety, and the section Simpeteria
Ottley (12 species) containing L. strigosus, L. strigosus var.
hirtellus, and L. tomentellus. Isely (1981) reduced
L. tomentellus to a variety of L. strigosus.
Until present, the standard with blade attenuated into the claw,
the wings asymmetrically positioned and longer than the keel,
and the stigma penicillate, are the characters used to separate
the section Simpeteria from the section Microlotus.
However, these characters and those (e. g., density of the pubescence,
presence and shape of the bract, standard shapes) used to separate
L. salsuginosus and L. strigosus are not enough
to delimitate L. salsuginosus var. brevivexillus
and L. strigosus var. tomentellus. These are two
varieties of different species frequently confused.
The purpose of this article is to emphasize the most useful characters,
and to include news, to delimitate L. salsuginosus var.
brevivexillus and L. strigosus var. tomentellus.
MATERIALS AND METHODS
Specimens of herbarium, fruit and seed samples surveyed, were
from BRY, MEXU, NSMC, SD, US. The acronyms for the herbaria are
given according to Holmgren et al. (1990). Some samples were from
Desert Legume Program, Tucson (UAz). Morphological and anatomical
characters were examined with a stereoscopic microscope (at 40
x or less) and an optical microscope; both equipped with a camera
lucid. The testa topographic features were analysed on whole seeds
and portions of them mounted on brass-stubs, sputter-coated with
gold-palladium in a JFC-1100 and viewed at 15 kv with a Jeol JSM-T100
scanning electron microscope (SEM). The topographic features were
described according to Lersten (1981). Drawings of the characters
were prepared by the author.
L. salsuginosus (Greene) Greene
L. salsuginosus Greene var. brevivexillus Ottley
Lotus strigosus (Nutt.) Greene var. tomentellus Isely
Comment
(*) specimens mounted on the same sheet.
(**) the specimens on the sheet correspond to L. strigosus
var. tomentelllus, whereas the material into the envelope
attached, contains a mixture of the specimen with L. salsuginosus
var. brevivexillus.
Results and Discussion
| Table 1. Corolla, legume and seed characteristics to distinguish L. salsuginosus Greene var. brevivexillus Ottley and L. strigosus (Nutt.) Greene var. tomentellus Isely. | ||
| L. salsuginosus var. brevivexillus | L. strigosus var. tomentellus | |
| COROLLA | (Fig. 1, A-C-E) | (Fig. 1, B-D-F) |
| Standard venation | The veins show a curved course in the base of the blade. | The veins show a ± straight course in the base of the blade. |
| Wing | The auricle is always exposed | The auricle is obscured by the upper margin folded downwards. |
| Keel | The upper margin straight. The apex obtuse. | The upper margin convex or slightly so. The apex acute. |
| LEGUME | (Fig. 1, G) | (Fig. 1, H) |
| The hard and persistent base of the style always recurved | The hard and persistent base of the style always short and straight. | |
| SEED | (Fig. 2, A-a) | (Fig. 2, B-b) | (Fig. 2, C) | (Fig. 2, D) |
| Seed shape | globose | globose | globose | laterally compressed |
| Seed shape in outline (Face view) | ovate-round | quadrangular to round | circular | circular, rarely quadrangular |
| Testa surface(At 40 x or less) | smooth | smooth or near so | rugose | sinuate rugose |
| Radicular lobe | inconspicuous | discernible | discernible | prominent |
| Lens | small mound | small mound | conspicuous | conspicuous |
| Hilum elevation | superficial | superficial | superficial | sunken in lateral notch |
| Hilar rim | conspicuously discoloured | concoloured | concoloured | concoloured |
| Micropyle | bifurcate | bifurcate | bifurcate | deltoid |
| Testa topography, on mid-face | papillose (small papillaes) | reticulate | reticulate sinuate or non sinuate, with mounds | papillose sinuate, with or without very small mounds |
Acknowledgments
I wish thank to the staff of the institutions who supplied the
specimens and fruit-seed samples studied. My special thank to
Mario Sousa S. and Maru García Peña who borrowed
most of the specimens studied. Thank Liliana Katinas for providing
a number of suggestions that helped to improve earlier manuscripts
and Rafael Urrejola for technical assistance using SEM.
REFERENCES
Greene, E. L. 1890. Enumeration of the North American Loti. Pittonia 2: 133-150.
Holmgren, P. K. , N. H. Holmgren and L. C. Barnett. 1990. Index Herbariorum. P. 1. The Herbaria of the World. [Regnum Veg. 120]. NY Bot. Gard., Bronx.
Isely , D. 1981. Leguminosae of the United States. III. Subfamily Papilionoideae: Tribes Sophoreae, Podalyrieae, Loteae. Mem. NY Bot. Gard. 29(3): 124-264.
Lersten, N. R. 1981. Testa Topography in Leguminosae, Subfamily Papilionoideae. Proc. Iowa Acad. Sci. 88(4): 180-191.
Ottley, A. M. 1923. A revision of the Californian species of Lotus. Univ. California Publ. Bot. 10: 189-305.
Ottley, A. M. 1944. The American Loti with special consideration of a proposed new section, Simpeteria. Brittonia 5(2): 81-123.
In our laboratory, all combinations of somatic
cell hybrids have been carried out among a graminous plant, rice
(Oryza sativa L.) and three leguminous plants, soybean
(Glycine max (L.) MERR.), birdsfoot trefoil (Lotus corniculatus
L.) and alfalfa (Medicago sativa L.). We report here asymmetric
somatic hybrid of birdsfoot trefoil and alfalfa.
Materials and Methods
The calli of birdsfoot trefoil cv. Viking
and alfalfa cv. Rangelander were used for the isolation of protoplasts.
The enzyme solution for the protoplast isolation of both birdsfoot
trefoil and alfalfa was constituted with 4% Cellulase Onozuka
RS, 1% Macerozyme R-10, 0.2% Pectolyase Y-23 and 0.6 or 0.7 M
mannitol. The division of birdsfoot trefoil protoplasts was inhibited
by the treatment of 10 mM iodoacetamid (IOA). The protoplasts
of alfalfa were irradiated by 40 kR of X-rays. The fused protoplasts
were then cultured in the KM8p medium (Kao and Michayluk, 1975)
by the agarose-beeds and nurse culture methods. The isozymes of
obtained calli and regenerated shoots were examined on aminopeptidase
(AMP), esterase (EST), glutamate dehydrogenase (GDH) and catalase
(CAT).
Results and Discussion
The 155 callus lines were obtained from the
asymmetrc somatic cell fusion of birdsfoot trefoil and alfalfa.
Among these calli, 17 callus lines were identified as somatic
cell hybrids by the analyses of isozymes (Table 1). After one
month of subculture, most of the hybrid calli, however, altered
the isozyme banding patterns to those of birdsfoot trefoil on
the medium of Murashige and Skoog (1962) (MS medium) with 4 mg/l
1-naphthaleneacetic acid (NAA) and 2.5 mg/l kinetin or with 1.5
mg/l indole-3-acetic acid (IAA) and 1.5 mg/l 6-benzyladenine (BA).
This result means that most of the alfalfa chromosomes irradiated
by X-rays disappeared during the subcultures. Niizeki et al. (1989)
reported that the shoot regeneration did not occur from the symmetric
somatic hybrid calli of birdsfoot trefoil and alfalfa. On the
other hand, in this study shoot regeneration occurred from the
asymmetric somatic cell hybrid calli. All isozyme banding patterns
of these shoots investigated so far, however, were the same as
those of birdsfoot trefoil. These results show that it is possible
to regenerate the shoots from the cybrid calli derived from the
asymmetric hybrid in which donor protoplasts irradiated by X-rays,
while it seems to be impossible to regenerate the shoots from
the symmtrical somatic hybrids which have both parent chromosomes.
This phenomenon was also observed in the somatic cell hybrid of
birdsfoot trefoil and soybean (Niizeki et al. 1990, 1994).
| Table 1. Isozyme analyses of asymmetrical somatic cell hybrids of alfalfa and birdsfoot trefoil. | |||||||||||||
| Total colonies obtained by protoplast fusion = 155.
Number of obtained hybrid clones = 17. | |||||||||||||
| Hybrid clone | Plant regeneration | ||||||||||||
| I-1 | |||||||||||||
| I-3 | |||||||||||||
| I-7 | |||||||||||||
| I-16 | |||||||||||||
| I-20 | |||||||||||||
| I-27 | |||||||||||||
| I-29 | |||||||||||||
| I-31 | |||||||||||||
| I-78 | |||||||||||||
| I-82 | |||||||||||||
| II-14 | |||||||||||||
| II-34 | |||||||||||||
| II-44 | |||||||||||||
| II-45 | |||||||||||||
| II-46 | |||||||||||||
| II-47 | |||||||||||||
| II-63 | |||||||||||||
* : +, plant regeneration; -, no plant regeneration.
Isozyme pattern A: Investigate the calli cultured for one month;
Isozyme pattern B: Investigate the calli cultured for two months;
Isozyme pattern C: Investigate the regenerated plant.
A: Isozyme band pattern of alfalfa; B: Isozyme band pattern of
birdsfoot trefoil; A+B: Isozyme band pattern of both parents.
References
Kao, K.M. and M.R.Michayluk 1975. Nutritional requirements for growth of Vicia hajastana cells and protoplasts at a very low population density in liquid media. Planta 126: 105-110.
Murashige, T. and F. Skoog 1962. A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol. Plant 15: 473-497.
Niizeki, M. and K. Saito 1989. Callus formation from protoplast fusion between leguminous species of Medicago sativa L. and Lotus corniculatus L. Japan. J. Breed. 39: 373-377.
Niizeki, M., K. Kihara and K-N. Cai 1994. Somatic hybridization between birdsfoot trefoil (Lotus corniculatus L.) and soybean (Glycine max L.). In Biotechnology in Agriculture and Forestry, Vol.27 "Somatic Hybridization in Crop Improvement I", Y.P.S. Bajaj (ed), Springer-Verlag pp132-144.
Niizeki, M., K. Cai, M. Kihara, S. Nakajo and T. Harada 1990. Somatic cell hybrids between birdsfoot trefoil and soybean. Lotus Newslett. 21: 14-17.
A morphological and architectural study was made on an herbaceous species of Fabaceae, Lotus tenuis Walds. et Kit (narrow birds-foot trefoil), a perennial pasture legume.
This species was introduced into South America (in Argentina, in 1930), from Europe, and became established and naturalized on the Flooding Pampa (Burkart, 1952). Agronomists are selecting various commercial varieties for best performance an alternative to Medicago sativa (lucerne grass) affected by flooding, a very common disturbance in this region (León and Oesterheld, 1982).
This research represents a basic study of the morphology and growth habit of Lotus tenuis, that is essential for a correct grazing management.
The study was conducted during 1993-94, seeds sown in May 17,
at experimental fields of the Faculty of Agronomy, Buenos Aires,
Argentine,(34º 35'S, 58º 29'W), with seeds from a cultivar
provided by AgroVerónica, Verónica, Buenos Aires
Province. Twenty isolated plants were sampled to determined the
architectural unit before nature defoliation.
The architectural unit of any plant are the different (morphological and functional) axes categories (Barthélémy, 1991). These axes are formed by shoot-units (Bell, 1994), each derived from one apical meristem.
The architectural unit is determined by two shoot categories: vegetative and reproductive (flowering branches). The leaves have spiral arrangement and have a single axillary bud with 2 prophylls (&) each with a bud, which can develop vegetative or reproductive branches. The first branches (prb) develop from the prophyllar buds of the axillary complex. Sometimes only one of the prophyllar bud develops, whilst the another and the axillary bud, remain dormant.
The vegetative shoots are basitonic. All vegetative axes -main
axis (ma) and branches (b)- are monopodial with continuous growth
. Shoot units initially develop horizontally, then change growth
direction and procede to develop vertically (Fig. 1 A-D). The
proximal nodes of the shoot units have the capacity to produce
adventitious roots (ar), this represents a plagiotropic form during
establishment (Fig. 1 C-D). The converse reorientation occurs
once for the initial shoot unit of many herbaceous plants (Bell,
1994).
The apical meristematic activity is limited, when the growing season finishes in summer after flowering (Fig 1 C & D), all the apical meristems die (md).
During the first year the plant develops the crown, formed by a group of closed branches arising at the basal nodes of the main axis, first and second order branches, near the soil (Fig. 1 B-D).
The reproductive branching pattern is acrotonic (Fig. 1 C). The
flowering branches (fb) arise from the axillary buds of the upper
nodes of all vegetative axes.
The architecture (growth-form, habit) is determined by one orthotropic, sympodial axis (ma), with limited growth; orthotropic basitonic vegetative branches with a similar pattern (reiterations) occur (Fig. 1 D).
The plant repeats its elementary architecture (the architectural unit, building by shoot units).
At the end of growing season, when the shoots units of the previous year die, the proximal nodes lateral buds of the plagiotropic phase of the branches (Fig. 1 D) give rise new reiterations -proleptic, partial and adaptive- (nr). The old dead stems, of previous year, with adventitious roots, remain as stolons or rhizomes. These regrowth shoots may be vulnerable to damage by too-intensive grazing. The importance of the plagiotropic development of the basal shoots is crucial to long lived axillary meristems.
The independence of the different modules from the main axes may
develop, as an important way of propagation, in the second or
third period of growth, although it's not clear, the importance
of this strategy, during the establishment.
The architectural model responds to Tomlinson's. Shoot units initially
develop horizontally, then change growth direction, in established
phase as in the Tomlinson's model (Hallé, et al., 1978).
References.
Barthélémy D. 1991. Levels of organization and repetition phenomena. Acta Biotheoretica 39: 309-323.
Bell AD. 1994. A Summary of the Branching Process in Plants. In Ingram, D.S. & Hudson, A. (eds.), Shape and Form in Plants and Fungi. Linn. Soc. Symposium Series 16, pp. 119-142. London: Academic Press.
Burkart A. 1952. Las Leguminosas argentinas silvestres y cultivadas.Ed. ACME, Bs. As. 2da. Edición. Pp.590.
Hallé F, Oldeman RAA & Tomlinson PB. 1978. Tropical trees and forests. Springer, Berlín. Pp. 441.
León RJC y Oesterheld M. 1982. Envejecimiento de pasturas implantadas en el Norte de la Depresión del Salado, un enfoque sucesional. Rev.Fac. Agron. Bs. As. 3: 41-49.
:
Lotus tenuis A-E; diagrammatic representation of 5 growing stages: A.- First stage: The main axis bears at the cotyledonary node, one shoot with a prophyllar branch, at each cotyledon axil; all the axes show continuous growth; B.-Second stage : Main axis with basitonic continuous branches from cotyledons to 4-node. The prophyllar branches are larger than cotyledonary shoots; C.- Third stage: Adult phase previous to reproductive stage with complete branching pattern (second and third order branches); D.- Fourth stage: Adult phase with flowering branches; E.- Last stage: Apical meristem of all shoots die. The reiterations (broken line) arise from the crown.
Arrows indicate that stems are still growing. In C all the axes with curved arrows indicate a larger growth than the main axis. In B & C Stars and asterisks represented second order branches. Cotyledons are represented schematically and are not to scale; normal foliage leaves are not represented. In D, little stars represent second order flowering branch.
Abbreviations: ar: adventitious roots; b1, b2, b3 and b4: first node axillary branch to four node branch; c: cotyledon; cs: cotyledonary shoot; fb: flowering branches, ma: main axis; md: meristem death; prb: prophyllar branch; re: reiterations.
Arrows indicate that stems are still growing. Stars represent second order flowering branch. Cotyledons are represented schematically and are not to scale; normal foliage leaves are not represented.
Isolation, chemical structures and biological activity of the
lipo-chitin oligosaccharide nodulation signals from Rhizobium
etli. Cardenas, L.; Dominguez, J.; Quinto, C.; Lopez-Lara,
I. M.; Lugtenberg, B. J. J.; Spaink, H. P.; Rademaker, G. J.;
Haverkamp, J.; Thomas-Oates, J. E. Departamento de Biologia Molecular
de Plantas, Instituto de Biotecnologia, Universidad Nacional Autonoma
de Mexico, Mexico. Plant Molecular Biology vol. 29 (3): p.453-464.
Publication Year: 1995
Rhizobium etli is a microsymbiont of plants of the genus
Phaseolus. Using MS the lipo-chitin oligosaccharides (LCOs)
that are produced by R. etli strain CE3 were identified.
They are N-acetylglucosamine pentasaccharides of which the nonreducing
residue is n-methylated and n-acylated with cis-vaccenic acid
(C18:1) or stearic acid (C18:0) and carries a carbamoyl group
at C4. The reducing residue is substituted at the C6 position
with O-acetylfucose. Analysis of their biological activity on
the host plant Phaseolus vulgaris shows that these
LCOs can elicit the formation of nodule primordia which develop
to the stage where vascular bundles are formed. The formation
of complete nodule structures, including an organized vascular
tissue, is never observed. Considering the close resemblance of
the R. etli LCO structure of those of R. loti, the
ability of R. etli strains to nodulate various Lotus
species and of R. loti to nodulate P.vulgaris was
tested. The results show that R. etli is able to nodulate
Lotus plants. However, several Lotus species are
only nodulated when an additional flavonoid independent transcription
activator (FITA) nodD gene is provided. Phaseolus plants
can also be nodulated by R. loti bacteria, but only when
the bacteria contain a FITA nodD gene. Apparently, the type of
nod gene inducers secreted by the plants is the major basis for
the separation of Phaseolus and Lotus into different
cross inoculation groups.
A chromosome atlas and interspecific-intergenic index for Lotus
and Tetragonolobus (Fabaceae). Grant, W. F. Department
of Plant Science, P.O. Box 4000, McGill University, Macdonald
Campus, Ste Anne de Bellevue, QC H9X 3V9, Canada. Canadian Journal
of Botany vol. 73 (11): p.1787-1809 Publication Year: 1995
Basic chromosome numbers in Lotus are x = 5, 6 and 7. It
is considered that evolution has proceeded in the genus by means
of a descending aneuploid series from an 8-chromosomed ancestor.
Chromosome numbers for species of Tetragonolobus are based
on x = 7. Somatic chromosome markers are reported for 108 species
and 38 varieties. Chromosome numbers are reported for the first
time for 5 species (L. hamatus, L. haydonii, L. hintoniorum,
L. mearnsii and L. utahensis; all 2n = 14), 6 varieties (L.
argophyllus var. argenteus, L. dendroideus var.
traskiae, L. heermanii var. orbicularis, L. junceus var.
biolettii, L. strigosus var. hirtellus, L. strigosus var.
tomentellus; all 2n = 14) and L. uliginosus subsp.
vestitus (2n = 12). Natural diploid, tetraploid and hexaploid
plants are reported for L. alpinus. Several species are
reported as possessing B chromosomes. Mixoploidy is reported to
occur in L. alpinus, L. glacialis and L. glareosus.
In addition, chromosome numbers are given for plants regenerated
from calluses grown in tissue culture having heteroploidy, euploidy
and mixoploidy. Root nodules are reported with tetraploid and
octoploid cells in addition to the normal number of chromosomes.
Trisomic series have been partially developed in L. tenuis
and L. uliginosus. Polytene chromosomes were observed in
suspensor cells of three species of Lotus. Feulgen cytophotometric
measurements, to determine the DNA nuclear content, were made
for 16 species of Lotus and one species of Tetragonolobus.
The majority of the studies in Lotus concerned the economic
species L. corniculatus, L. tenuis and L. uliginosus.
Interspecific hybridization was carried out in different combinations
between diploids, autoploids and amphidiploids. Intergeneric hybrids
were attempted by somatic hybridization, protoplast fusion and
assymetric hybridization between Lotus and other species
(Glycine max, Medicago sativa, Oryza sativa).
Effect of inoculation and nitrate on nitrate reductase activity
and acetylene reduction activity in Lotus sp.- Rhizobium
loti symbiosis. Diaz, P.; Borsani, O.; Monza, J. Departamento
de Bioquimica, Facultad de Agronomia, Av. E. Garzon 780 C.P. 12900,
Montevideo, Uruguay. Symbiosis (Rehovot) vol. 19 (1): p.53-63.
Publication Year: 1995
The effects of nitrate and the Rhizobium strain used in
the inoculation on acetylene reduction activity (ARA), nitrate
reductase activity (NRA) and nitrate concentration in tissues
of two Lotus species inoculated with different Rhizobium
loti strains were examined. ARA in the symbiosis Lotus
corniculatus-R. loti T1 strain was inhibited 90% by nitrate
compared with 36% in the L. tenuis-R. loti Y3 symbiosis.
NRA in leaves and nitrate concentration in stems were modified
by inoculation. L. tenuis and L. corniculatus nodulated
by R. loti T1 strain had lower nitrate concentration in
the stem than when the same plants were nodulated by R. loti
Y3 and U226 strains and the non-nodulated plants. Inoculation
increased the NRA expression in leaf tissues of Lotus spp.
nodulated by R. loti T1 strain and the nitrate concentration
was similar to that found in non-nodulated plants.
Forage halophytes in the Mediterranean basin. Le Houerou,
H. N. 327 rue A. L. De Jussieu, 34090 Montpellier, France. Book
Title: Halophytes and biosaline agriculture. p.115-136. Publication
Year: 1995. Editors: Choukr-Allah, R.; Malcolm, C. V.; Hamdy,
A. Publisher: Marcel Dekker Inc. New York, USA ISBN: 0-8247-9664-0
It was shown that out of 700 Mediterranean halophyte species,
27.5% were from the Chenopodiaceae, 15% from the Poaceae, 6% from
the Asteraceae and 5% from the Caryophyllaceae, Fabaceae and Zygophyllaceae;
70% were perennial and 30% annual or biennial. The most common
tree species was Tamarix, the most common shrubs Salicornia,
Salsola, Suaeda and Atriplex, the most common perennials
Aeluropus, Sporobolus, Puccinellia and the most common
annual species Hordeum maritimum, Lepturus cylindricus, Frankenia
and Melilotus. The halophytic vegetation was described
and aspects of the palatability (ratio of feed intake:fodder on
offer) and preference; primary productivity (aboveground biomass
of Atriplex halimus was 10-15 t DM/ha and annual productivity
2-5 t DM/ha); grazing and nutritive value (digestible DM 40-70%,
digestible OM 50% and CP content 10-12%); and cultivation (Atriplex
nummularia, A. semibaccata and Myoporum insulare grown
in Australia and A. canescens and A. lentiformis
in the USA) were discussed. Many salt tolerant fodder species
used in land reclamation with or without irrigation using saline
water (Festuca arundinacea, Sporobolus, Trifolium fragiferum,
Lotus corniculatus, Lolium rigidum, Hordeum vulgare, Melilotus
alba, M. italica and Medicago spp.) gave DM yields
of 5-20 and 2-10 t/ha, respectively.
Comparison of conventional and alternative nursery weed management
strategies. Calkins, J. B.; Swanson, B. T. Dept. Hort. Sci.,
Univ. Minn., St. Paul, MN 55108, USA. Weed Technology vol. 9 (4):
p.761-767. Publication Year: 1995 ISSN: 0890-037X
In a field plot at the University of Minnesota, St. Paul, soil
cultivation (3 to 5 times/yr) and herbicide management (oxadiazon,
3.92 kg ai/ha), agricultural standards for reducing weed competition,
were compared to 3 alternative nursery field management systems
regarding weed suppression: 'Norcen' bird's-foot trefoil (Lotus
corniculatus) companion crop, 'Wheeler' winter rye cover crop/mulch
and grass sod (80% 'Eton' perennial ryegrass (Lolium perenne)
and 20% 'Ruby' red fescue (Festuca rubra)). Field management
treatment had a significant effect on observed weed populations.
Weed densities were also subject to yearly variations caused by
climate and endogenous weed life cycles. Herbicide management
(oxadiazon) consistently provided the best control of undesired
vegetation (0.3 weeds/m2) followed by the grass sod (0.7 weeds/m2),
Wheeler rye cover crop/mulch (1.7 weeds/m2), Norcen bird's-foot
trefoil companion crop (8.6 weeds/m2), and cultivated (55.7 weeds/m2)
treatments. Although the grass sod treatment provided excellent
control of undesired vegetation, as an alternative to cultivation
and herbicide use, it proved to be excessively competitive with
the nursery crop. The bird's-foot trefoil treatment quickly became
infested with broadleaf weeds the eradication of which proved
difficult. The Wheeler winter rye cover crop/mulch field management
system provided acceptable weed control combined with other beneficial
effects on the plant/soil environment. Results support the effectiveness
of Wheeler winter rye and perhaps other allelopathic cover crop/mulch
systems in controlling undesired vegetation in horticultural field
production systems.
Meiosis and seed production in plants of different populations
of birdsfoot trefoil (Lotus corniculatus L.). Nikolaichuk,
V. I. Uzhgorod University, Uzhgorod, Ukraine. Tsitologiya i Genetika
vol. 29 (4): p.61-66. Publication Year: 1995 ISSN: 0564-3783
PMC meiosis was studied in 3 natural populations and 4 varieties.
The frequency of disturbances at different stages of meiosis was
low, not exceeding 12.5% at the tetrad stage in the variety Smolens'kii.
Plants of this variety had the lowest pollen fertility and, accordingly,
the lowest seed set.
Rhizomatous Lotus corniculatus L.: I. Taxonomic and
cytological study. Beuselinck, P. R.; Li, B.; Steiner, J.
J. USDA-ARS, Plant Genetics Research Unit, Columbia, MO 65211,
USA. Crop Science vol. 36 (1): p.179-185. Publication Year: 1996
ISSN: 0011-183X
Wild, putative L. corniculatus accessions from Morocco
differ distinctly from domesticated L. corniculatus in
that they produce rhizomes. Rhizomes may be useful in increasing
stand persistence of domesticated L. corniculatus. The
objective of this study was to identify to the species level the
wild Lotus accessions from Morocco (G31272, G31273, G31276,
G31298 and G31317) that present rhizomatous growth. Comparative
morphological and cytological analyses, and intercrossing with
L. corniculatus, were used in this study. Six morphological
characters that distinguish L. corniculatus and L. uliginosus
(the only species in the genus Lotus recognized as producing
rhizomes) were used to categorize taxonomically the Moroccan accessions.
The Moroccan accessions were morphologically similar to L.
corniculatus with the exception of the rhizome trait. The
accessions were tetraploid with 2n = 4x = 24 somatic chromosomes.
Karyotype analyses detected more similarities than differences
between the Moroccan accessions and Norcen. Progeny were produced
from intercrosses between L. corniculatus cultivars Norcen
and AU Dewey and the Moroccan accessions. Hybridity of progeny
was verified by morphological and RAPD analyses. A sample of reciprocal
F1 progeny were tetraploid, fertile and consistent in their production
of rhizomes. A combination of morphological, chromosome, and karyotype
analyses confirmed accessions G31272, G31273, G31276, G31298,
and G31317 as L. corniculatus. This is the first description
of L. corniculatus with rhizomes.
Proanthocyanidins from Lotus corniculatus. Foo,
L. Y.; Newman, R.; Waghorn, G.; McNabb, W. C.; Ulyatt, M. J. NZ
Institute for Industrial Resesarch and Development, P.O. Box 31-310,
Lower Hutt, New Zealand. Phytochemistry vol. 41 (2): p.617-624.
Publication Year: 1996 ISSN: 0031-9422
The chemical structure of the purified proanthocyanidin polymers
of Lotus corniculatus was analysed by 13C NMR and by mild
acid catalysed degradation in the presence of excess of phloroglucinol.
The NMR data showed that the polymer was partially glycosidated
with a number average MW in the range 1800-2100 (6 to 7 flavanoid
units). The products from phloroglucinol scission reaction indicated
the extender flavan units to consist mostly of epicatechin (67%)
and epigallocatechin (30%), with minor amounts of catechin and
epiafzelechin units, which were linked together predominantly
by C-4/C-8 interflavanoid bonds. The polymer chains were terminated
mostly by catechin (83%) and, to a lesser extent, by epicatechin
(16%).
Taproot tip penetration and young seedling growth in relation
to root-hair adhesion among surface-sown legume species. Morita,
O.; Iwabuchi, K.; Goto, M.; Ehara, H. Faculty of Bioresources,
Mie University, Tsu, Mie 514, Japan. Nippon Sochi Gakkaishi =
Journal of Japanese Society of Grassland Science vol. 40 (4):
p.437-442. Publication Year: 1995 ISSN: 0447-5933
Seeds of white clover (Trifolium repens), alsike clover
(T. hybridum), red clover (T. pratense), crimson
clover (T. incarnatum), birdsfoot trefoil (Lotus corniculatus),
alfalfa (Medicago sativa) and common vetch (Vicia sativa)
were surface-sown on yellow soil under controlled conditions with
25 deg C and 100% RH. Penetration percentage of taproot tips,
mean days for taproot penetration, and hypocotyl and root growth
of three adhesion types in germination behaviour were examined
for five days to decide the adhering function of taproot hairs.
The three adhesion types in legumes were contact-adhesion, partial-adhesion
and non-adhesion, depending on the degree of adhesion in the taproot
hairs. Ninety percent of taproot tips of the contact-adhesion
type in white clover, alsike clover, birdsfoot trefoil and alfalfa
penetrated into the soil, being significantly higher than that
of partial-adhesion type. The same tendency was observed in red
clover, crimson clover and common vetch. The mean time for taproot
tip penetration of the contact-adhesion type was shorter than
that of the partial-adhesion type in all species examined. Length
and proportion of taproot exposed on the soil surface were shorter
in the contact-adhesion type than in the partial-adhesion type.
The hypocotyl-root ratio in length was highest in the contact-adhesion
type, followed by partial-adhesion type and non-adhesion types.
Therefore, good adhesion of taproot hairs to the surface enhanced
the hypocotyl growth as compared with taproot growth, and poor
adhesion of taproot hairs enhanced taproot growth. It is suggested
that the contact-adhesion type of germination behaviour would
provide good establishment compared with partial-adhesion and
non-adhesion types.
Effect of adhesion of taproot hairs to the soil surface on
germination behaviour in surface-sown legume species. Morita,
O.; Iwabuchi, K.; Goto, M.; Ehara, H. Faculty of Bioresources,
Mie University, Tsu, Mie 514, Japan. Nippon Sochi Gakkaishi =
Journal of Japanese Society of Grassland Science vol. 40 (4):
p.429-436. Publication Year: 1995 ISSN: 0447-5933
White clover (Trifolium repens), alsike clover (T. hybridum),
red clover (T. pratense), crimson clover (T. incarnatum),
birdsfoot trefoil (Lotus corniculatus), alfalfa (Medicago
sativa), and common vetch (Vicia sativa) were sown
on the surface of yellow paddy field soil under controlled conditions
at 25 deg C and 100% RH. Some morphological characteristics of
the taproot in relation to germination behaviour were measured.
Elongating taproots pushed the seed backwards and grew without
penetration of their tips into the soil. After root hairs developing
on taproots adhered to the surface, anchoring the seedlings, root
tips penetrated into the soil. Germination behaviour was classified
into three types: (i) taproot hairs that developed initially adhered
to the soil surface, thus taproots grew in contact with the soil
surface and root tips penetrated into the soil (contact-adhesion
type); (ii) taproot hairs adhered partially to the soil surface,
a part of the taproot was not in contact with the surface, but
root tips penetrated (partial-adhesion type); and (iii) taproot
hairs failed to adhere to the surface, taproots were not in contact
with the soil, and failed to penetrate into the soil (non-adhesion
type). White clover and birdsfoot trefoil had a higher percentage
of the contact-adhesion type in germination. Alsike clover, red
clover, crimson clover and alfalfa had higher percentages of the
partial-adhesion type, and common vetch had a higher percentage
of the non-adhesion type. The percentage of contact-adhesion type
seedlings was related to the ratio between length of root hair
and root diameter in the legume species. The adhering area that
was bound on the soil surface by taproot hairs was significantly
larger in the contact-adhesion type than in the partial-adhesion
type. It is suggested that an adhering function of taproot hairs
in surface-sown legume seedlings may secure good penetration of
root tips before establishment can be achieved.
Novel and complex chromosomal arrangement of Rhizobium loti
nodulation genes. Scott, D. B.; Young, C. A.; Collins-Emerson,
J. M.; Terzaghi, E. A.; Rockman, E. S.; Lewis, P. E.; Pankhurst,
C. E. Molecular Genetics Unit, Department of Microbiology and
Genetics, Massey University, Palmerston North, New Zealand. Molecular
Plant-Microbe Interactions vol. 9 (3): p.187-197. Publication
Year: 1996 ISSN: 0894-0282
A mutational and structural analysis of Rhizobium loti
nodulation genes in strs NZP2037 and NZP2213 was carried out.
Unlike the case with other Rhizobium strs examined to date,
nodB was found on an operon separate from nodACIJ. Sequence analysis
of the nodACIJ and nodB operon regions confirm that R. loti
common nod genes have a gene organization different from that
of other Rhizobium spp. At least 4 copies of nodD-like
sequences were identified in R. loti. The complete nucleotide
sequence of one of these, nodD3, was determined. A new host-specific
nod gene, nolL, was identified adjacent to nodD3. NolL shares
homology NodX and other O-acetyl transferases. Mutational analysis
of the nod regions of strains NZP2037 and NZP2213 showed that
nodD3, nodI, nodJ, and nolL were all essential for R. loti
strs to effectively nodulate the extended host Lotus pedunculatus,
but were not necessary for effective nodulation of the less restrictive
host, Lotus corniculatus. Both nodD3 and nolL were essential
for R. loti strs to nodulate Leucaena leucocephala.
Evaluation and characterization of Lotus corniculatus
accessions in spaced and dense stand conditions. (Valutazione
e caratterizzazione di accessioni di Lotus corniculatus
a piante spaziate e a semina fitta.) Negri, V.; Francia, U.;
Veronesi, F. Istituto di Miglioramento Genetico Vegetale, Universita
degli Studi, Perugia, Italy. Rivista di Agronomia vol. 29 (2):
p.160-164. Publication Year: 1995 ISSN: 0035-6034
In forage plants, single plant evaluation is often reported to
be of little interest in predicting sward performance. With the
aim of assessing the reliability of spaced plant evaluation in
screening birdsfoot trefoil germplasm for breeding purposes, a
spaced plant trial and a dense stand trial were set up. Nine natural
populations were studied in both trials. The following agronomic,
physiological and qualitative characters were recorded in 1993:
winter growth, spring regrowth, first flower date, average stem
length, total dry matter yield, crude protein, crude fibre, ash,
in vitro dry matter digestibility, milk feeding units and meat
feeding units. Polcanto, Macerata and Canetra were the most promising
natural populations. The data collected for each character and
for each population in the spaced plant and dense stand trials
showed substantial agreement. When screening birdsfoot trefoil
accessions from sites with different ecological conditions, evaluation
of spaced plants appears to be reliable in predicting sward performance.
Use of herbicides for the chemical protection of non-traditional
forage crop seed stands. (Vyuziti herbicidu v chemicke ochrane
semenarskych porostu netradicnich picnin.) Tesar, O. Vyzkumny
Ustav Picninarsky, 664 41 Troubsko, Czech Republic. Scientific
Studies - Research Institute for Fodder Plants (No. 13): p.91-104.
Publication Year: 1995
One pre-sowing and 14 post-em. herbicides were compared in seed
crops of the annual forage legumes Melilotus albus, Trigonella
coerulea, Tetragonolobus purpureus, Lotus ornithopodioides and
Malva verticillata in 1993 and 1994. The most effective combinations
were imazethapyr-ammonium + pyridate + rapeseed oil in T. coerulea
and M. albus with yield increases, no phytotoxicity and
95.7-100% control of Amaranthus sp. and 67.8-71.5% control
of Chenopodium sp. In M. verticillata, metamitron
+ triclopyr, metamitron + phenmedipham or desmedipham, and metamitron
+ fluazifop-P-butyl or haloxyfop gave 72.1-90.7% weed control
without phytotoxicity but crop yields were unaffected. T. purpureus
and L. ornithopodioides trials were unsatisfactory.
Seed multiplication of alpine grasses and herbs. (Saatgutvermehrung
alpiner Graser und Krauter.) Krautzer, B. Bundesanstalt fur
Alpenlandische Landwirtschaft Gumpenstein, 8952 Irdning, Austria.
Rasen-Turf-Gazon vol. 26 (4): p.123-131. Publication Year: 1995
ISSN: 0341-9789
Short descriptions are given of 7 grasses, 4 legumes and 6 forbs
regarded as promising for use in mixtures for resowing damaged
areas at high altitude and suitable for commercial seed production
at lower altitude. Information is presented on seed characteristics,
1000-seed weight, germination and seed quality. The latter was
comparable with that of commercial seed of lowland species. Seed
yields of Festuca nigrescens and Poa alpina decreased
with increasing altitude of origin, but adaptation to high altitude
may be more important than yield. In Trifolium pratense
subsp. nivale the disease susceptibility of some strains
meant that their yield was not related to the altitude of origin.
Average seed yields of the grasses (F. nigrescens, F. pseudodura,
F. supina (F. airoides), F. violacea, Phleum alpinum,
P. hirsutum and Poa alpina) were 100-500 kg/ha and
those of the legumes (Anthyllis vulneraria, Lotus corniculatus,
Trifolium badium and T. pratense subsp. nivale)
were 30-350 kg/ha. The highest yielding forb was Dianthus superbus
(average 578 kg/ha); the other species (Arnica montana, Crepis
aurea, Leontodon hispidus, Melandrium rubrum and Plantago
montana) yielded 100-300 kg/ha. Potential