Melilotus Alba Research Articles

Linked symbiotic populations: analysis of polymorphism in nfr5 receptor gene by using molecular doking

In the present work a molecular genetic analysis of the receptor part of the nfr5 gene in 15 plants of the conjugate collection (the plant component Melilotus albus, the bacterial component Sinorhizobium meliloti) has been done. Was studied the LysM domains structure and found a high level of the nucleotide polymorphism in LysM domains of this gene. A clear relationship of nucleotide and amino acid polymorphism in the receptor region of the nfr5 gene with the genetic diversity of the rhizobial component (bacterial symbiotic locus nodD) was observed. Based on these data, the computer modeling of binding of the bacterial Nod-factor with two different variants of the plant receptor was performed.

Selection for late flowering and greater number of basal branches increases the leaf dry matter yield in Melilotus albus Desr.

Melilotus albus is recognised as an important source of forage for ruminant animals in rangelands, particularly some of the germplasm of Melilotus collected in Argentina. This study was designed to evaluate the effects of 2 years of selection in M. albus for late flowering and branching on forage yield in a 2-year field plot experiment and to evaluate the effects of selection for late flowering on photoperiodic requirements in a 1-year pot experiment under natural and artificial lighting conditions. Three populations were evaluated, namely original population (T), a population selected for late flowering and greater number of basal branches (ET1), and a population selected only for late-flowering plants (ET2). The field plot experiment showed that total DM yield per year was higher for ET1 and T than for ET2 in Year 1 and higher for ET1 than T and ET2 in Year 2. Relative leaf yield was higher for ET1 and ET2 than for T in both years. Leaf number was greater for ET1 than for ET2 and T in both years. The number of new basal and total branches was greater in ET1 than in ET2 and T for both years. The pot experiment showed that days to flowering, calculated as the average of natural and artificial lighting treatments, were higher in ET2 and ET1 (83.4 days ± 15 and 72.8 days ± 19, respectively), than in T (61.2 days ± 21). Supplementary lighting reduced days to flowering compared with natural lighting conditions for all populations (58.7 days ± 13 v. 86.1 days ± 12). Results showed that 2 years of selection proved to be efficient in breeding for late flowering and greater number of basal branches in M. albus. The longer vegetative stage observed in the improved populations can be explained by the selection of plants which require a longer photoperiod to flower. Selection for late flowering and greater number of basal branches resulted in a population with more leaves and higher relative leaf yield.

First Record of the European Rusted Flea Beetle,Neocrepidodera ferruginea(Scopoli, 1763), in North America (Coleoptera: Chrysomelidae: Galerucinae: Alticini)

The European rusted flea beetleNeocrepidodera ferruginea(Scopoli, 1763) is reported for the first time from Québec and Ontario, Canada. It was likely introduced into southern Ontario at an international port on the Great Lakes in early 1970s, or possibly earlier in the 1960s. However, the exact location and date of introduction could not be precisely determined. The flea beetle has since dispersed northeastwards and reached Aylmer, north of Ottawa River, in Québec, by 2003. This is about 375 km from Niagara Falls, where the oldest known specimens were collected in 1977. In 2009, various wild habitats and cultivated areas of Aylmer were surveyed. The host plants of the larvae could not be determined, but adults were swept from many plant species including various weeds and cultivated grasses:Alopecurus pratense(meadow foxtail),Dactylis glomerata(orchard-grass),Festuca rubra(red fescue-grass), andPoa pratensis(Kentucky blue-grass). Adults were also collected from flowers of several weeds:Astersp. (undetermined species),Aster novae-angliae(New England aster),Ambrosia artemisiifolia(small ragweed),Echium vulgare(viper’s bugloss),Nasturtium officinale(water cress),Melilotus alba(white sweet-clover),Hypericum perforatum(common St. John’s-wort),Lythrum salicaria(purple loosestrife),Ranunculus acris(buttercup), andSolidagospp. (goldenrods). Since larvae are known to develop inside the roots and central stems of cereals, this new alien species represents a threat to Canadian agriculture, particularly if it reaches the Prairies in western Canada, where cereals represent a considerable part of their economy.European rusted flea beetleandAltise ferrugineuse européenneare suggested for the English and French common names of this flea beetle, respectively.

Biological screening of various medicinal plant extracts for antibacterial and antitumor activities

Bioassays of 2 types (antibacterial and antitumor) were performed to show the biological activities of 16 different plants grown in Bolu, Turkey: Clinopodium vulgare L. subsp. vulgare L., Salvia verticillata L. subsp. amasiaca (Frey & Bornm.) Bornm., Salvia tomentosa Mill., Mentha pulegium L., Melilotus officinalis (L.) Desr., Melilotus alba Desr., Medicago lupulina L., Galega officinalis L., Xeranthemum annuum L., Cichorium intybus L., Plantago lanceolata L., Plantago major L. subsp. major, Fumaria officinalis L., Galium palustre L., Echium vulgare L., and Sambucus nigra L. For each plant, 3 different extracts (aqueous, ethanol, and methanol) were obtained, and a total of 48 extracts were evaluated. Antibacterial activity was evaluated with 10 bacteria, including Streptococcus pyogenes, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Serratia marcescens, Proteus vulgaris, Enterobacter cloacae, and Klebsiella pneumoniae by disk diffusion method. All plants except M. alba, M. lupulina, X. annuum, G. palustre, and S. nigra showed inhibitory activity against both gram-positive and gram-negative bacteria. The best inhibitory activity was observed with aqueous extract of M. officinalis (22.5 mm); it performed better than all positive controls (erythromycin, ampicillin, carbenicillin, tetracycline, and chloramphenicol; 7-20 mm) against P. aeruginosa. Antitumor activity was evaluated with Agrobacterium tumefaciens-induced potato disk tumor assay. The best antitumor activity was obtained with the methanolic extract of M. alba and aqueous extract of F. officinalis (100% tumor inhibition).

Meliloester, a New Melilotic Ester from Melilotus alba

A new melilotic ester, meliloester [2-ethyl-hexyl-3-(2-hydroxyphenyl) propionate], was isolated from the whole plant of Melilotus alba. Its structure was elucidated on the basis of spectroscopic and mass spectrometric analyses, including EI-MS, HR-MS, and UV, IR, 1D and 2D-NMR spectroscopic studies.

Lead accumulation and synthesis of non-protein thiolic peptides in selected clones of Melilotus alba and Melilotus officinalis

The accumulation of Pb, its effect on plant growth, and the synthesis of non-protein thiolic peptides were evaluated in clone MA-X of Melilotus alba and clone MO-A of Melilotus officinalis cultured in a greenhouse in artificially-polluted substrate with 200 and 1000mgPbkg−1. At 90 days of Pb exposure root growth was not affected, except at 1000mgPbkg−1 in MA-X. At this concentration hyperaccumulation value was exceeded in both clones, reaching more than 4800mgPbkg−1dry wt. in shoots of MA-X and more than 3400mgPbkg−1dry wt. in shoots of MO-A. Phytochelatins (PCs) and homophytochelatins (hPCs) were found in all cases for both species. Clone MA-X showed an increase in constitutive hPCs content in shoots whereas PC2, PC3 and hPC3 were synthesized in roots after 90 days of culture in 1000mgPbkg−1. On the other hand, MO-A synthesized a new PC (PC4) in shoots while in roots only hPC2 was found. Our results suggest that clones MA-X and MO-A show high Pb accumulation ability and that this capability can be related to the synthesis of PCs and hPCs.

Mineral composition of lucerne ( Medicago sativa) and white melilot ( Melilotus albus) is affected by NaCl salinity of the irrigation water

Most glycophytic forage legumes exhibit large reductions in biomass in response to saline growing conditions, although differences among species in salt tolerance exist. As several plant metabolic processes are affected by salinity, the nutritive value of these species to animals may be altered. Mineral concentration is an important component of plant nutritive value, and was evaluated in lucerne and white melilot under salt concentrations of 0, 55 and 110 mM NaCl in a glasshouse. Lucerne consistently accumulated higher concentrations of Na and Cl than white melilot. Calculated NaCl concentrations per unit DM reached 125 g/kg in lucerne and 39 g/kg in white melilot when irrigated with water containing 110 mM NaCl. In leaves of both species the Ca and Mg concentration decreased (P < 0.0001) with increasing salinity level, and there was an interaction (P < 0.0001) for these elements in which lucerne stems had decreases. The P concentration increased (P < 0.0001) in both species and the K concentration was affected only in lucerne stems. Among trace elements, Zn and Fe had marked decreases. Leaf and stem Zn concentration decreased in both species and Fe decreased more in leaves than in stems, but most analyzed microelements remained at acceptable levels for animal production. Detrimental changes in the mineral composition of forage species in response to salinity can be minimized by selecting appropriate species, such as white melilot. This may lead to improved animal production if biomass production, voluntary animal intake and digestibility can be maintained.

Ecology of Invasive Melilotus albus on Alaskan Glacial River Floodplains

Melilotus albus (white sweetclover) has invaded Alaskan glacial river floodplains. We measured cover and density of plant species and environmental variables along transects perpendicular to the Nenana, Matanuska, and Stikine Rivers to study interactions between M. albus and other plant species and to characterize the environment where it establishes. Melilotus albus was a pioneer species on recently disturbed sites and did not persist into closed canopy forests. The relationships between M. albus cover and density and other species were site-specific. Melilotus albus was negatively correlated with native species Elaeagnus commutata at the Nenana River, but not at the Matanuska River. Melilotus albus was positively correlated with the exotic species Crepis tectorum and Taraxacum officinale at the Matanuska River and T. officinale on the upper Stikine River. However, the high density of M. albus at a lower Stikine River site was negatively correlated with T. officinale and several native species including Lathyrus japonicus var. maritimus and Salix alaxensis. Glacial river floodplains in Alaska are highly disturbed and are corridors for exotic plant species movement. Melilotus albus at moderate to low densities may facilitate establishment of exotic species, but at high densities can reduce the cover and density of both exotic and native species.

Arbuscular mycorrhizal fungi on growth, nutrient status, and total antioxidant activity of Melilotus albus during phytoremediation of a diesel-contaminated substrate

This research evaluated the effects of arbuscular mycorrhizal fungi (AMF) on growth, nutritional status, total antioxidant activity (AOX), total soluble phenolics content (TPC), and total nitrate reductase activity (NRA) of leaves and roots of Melilotus albus Medik planted in diesel-contaminated sand (7500 mg kg(-1)). Seedlings of Melilotus either Non inoculated (Non-AMF) or pre-inoculated plants (AMF) with the AMF-inoculum Glomus Zac-19 were transplanted to non-contaminated or contaminated sand. After 60 days, diesel significantly reduced plant growth. AMF- plants had no significant greater (64% and 89%, respectively) shoot and leaf dry weight than Non-AMF plants, but AMF plants had lower specific leaf area. AMF-plants had significantly greater content of microelements than non-AMF plants. Regardless diesel contamination, the total AOX and TPC were significantly higher in leaves when compared to roots; in contrast, NRA was higher in roots than leaves. Diesel increased total AOX of leaves, but AMF-plants had significantly lower AOX than non-AMF plants. In contrast, roots of AMF-plants had significantly higher AOX but lower NRA than non-AMF plants. AMF-colonization in roots detected via the fungal alkaline phosphatase activity was significantly reduced by the presence of diesel. AMF-inoculation alleviated diesel toxicity on M. albus by enhancing plant biomass, nutrient content, and AOX activity. In addition, AMF-plants significantly contributed in higher degradation of total petroleum hydrocarbons when compared to non-AMF-plants.

Invasive sweetclover (Melilotus alba) impacts native seedling recruitment along floodplains of interior Alaska

Sweetclover (Melilotus alba) is a non-native legume that has formed dense and extensive patches along several rivers in Alaska. Our research objective was to determine if sweetclover impacts recruitment of native seedlings in floodplain habitats. To determine if sweetclover impacted recruitment, we conducted a removal experiment along two rivers in interior Alaska. When compared to areas where sweetclover was removed, areas with sweetclover had approximately 50% greater mortality of native seedlings, 25% less recruiting species, and a significant reduction in the quantity of light available to seedlings on floodplain surfaces. To determine if sweetclover shading was a mechanism that limited seedling recruitment, we grew eight common early-successional floodplain plant species in a greenhouse under a range of lighting conditions that were representative of shading under sweetclover. We observed that species restricted to the earliest seral stages of floodplain succession experienced greater reductions in biomass than species that persist into later stages of floodplain succession. Shading seedlings in a greenhouse did not lead to mortality during the growing season. However, when seedlings were over-wintered, we observed that greater shading during the growing season can result in higher seedling mortality. Our study indicates sweetclover invasions have created a novel shade environment in early seral floodplain plant communities, which has the potential to alter community composition. To preserve biodiversity and structure of plant communities, sweetclover should be actively managed to prevent its spread onto additional glacial rivers in Alaska.

Floral Scent Terpenoids Deter the Facultative FlorivoreMetrioptera bicolor(Ensifera, Tettigoniidae, Decticinae)

Non-pollinating florivores (animals feeding on floral resources) represent severe antagonists that have negative impacts on the plants' reproduction. Plants would thus benefit by excluding them from their flowers. In this study, we tested whether floral scent compounds that are attractive to many pollinators, also have the potential to prevent facultatively flower-feeding herbivores from consuming flowers. For feeding trials, we chose the bush cricket Metrioptera bicolor, a species that mainly consumes grasses, but also feeds occasionally on flowers. Linalool and β-caryophyllene (mono-and sesquiterpenoid, respectively) turned out to be effective antifeedants, while other floral scent compounds had no effect. Furthermore, bush crickets completely rejected flowers of Convolvulus arvensis (Convolvulaceae) and Melilotus alba (Fabaceae), while preferring flowers of Echium vulgare (Boraginaceae) over leaves. In addition to feeding experiments, excrement of bush crickets and other orthopterans were searched for pollen. Most individual bush crickets had pollen in their faeces, largely from Poaceae and Gymnosperms, suggesting accidental ingestion of wind-dispersed pollen, rather than targeted consumption of floral pollen. Our results support the hypothesis of a dual role of floral scents in attraction and defence.

Problem of Applying Sodium Selenate to Increase Selenium Concentration in Grassland Plants in Southern Belgium

In a survey of grasslands, mean selenium (Se) concentration in Holcus lanatus was 83 μg kg−1 (less than 100 μg kg−1, the minimal concentration protecting mammals from deficiency disorders). Despite rather high levels of soil extractable Se, plant Se availability was supposed to be low because of high soil humus concentration. A pot experiment with common grassland species showed contrasting responses to selenate addition (9 g Se ha−1 yr−1). Lolium perenne leaves reached 470 μg kg−1, and Trifolium pratense reached 292 μg kg−1. The controls were less than 100 μg kg−1. Leaves of others species showed greater values both in control and treated series and no significant difference. In a second pot experiment, Melilotus albus, a supposed secondary accumulator, and Lolium perenne as a control were submitted to moderate increased selenate additions (up to 45 g Se ha−1 yr−1). The results confirmed that Melilotus albus was a better accumulator with a leaf concentration that could reach the toxicity level of 2 mg kg−1.

White Sweetclover (Melilotus albus) and Narrowleaf Hawksbeard (Crepis tectorum) Seed Germination after Passing through Moose

AbstractWhite sweetclover and narrowleaf hawksbeard are nonindigenous invasive plant species in Alaska that are rapidly spreading, including into areas that are otherwise free of nonindigenous plants. There has been concern that native moose could be dispersing germinable seed from these plants after ingestion. To address this concern, a study was conducted involving tame moose at the University of Alaska Fairbanks Agriculture and Forestry Experiment Station, Matanuska Experiment Farm, Palmer, AK. Objectives were to determine if seeds from these two plant species could survive mastication and digestive passage through moose, whether this passage impacted seed germination, and whether seed passage rates were the same as similar sized Cr-mordanted fiber. In this study, narrowleaf hawksbeard seed rarely survived mastication and digestion with only five seedlings recovered from 42,000 germinable seed fed to the moose. About 16% of germinable white sweetclover seed (3,595 of 22,000) fed to the moose produced seedlings. Most of the sweetclover seedlings came from feces produced 2 and 3 d after feeding. In two moose, sweetclover seedlings were grown from fecal material that was passed 11 d after feeding, raising the possibility that seeds could be transported long distances after ingestion. Cr-mordanted fiber passage did not closely follow seedling producing seed, possibly because time in the rumen might reduce seed germination. Once roadsides in Alaska become infested with white sweetclover, moose can then serve as a transport vector of these weeds into river channels and floodplains, which are distant from roads. This information will impact white sweetclover management programs and alert land managers to the potential for other instances of wildlife-mediated seed dispersal.

An open‐flower mutant ofMelilotus alba: Potential for floral‐dip transformation of a papilionoid legume with a short life cycle?

This paper describes an open-flower mutant, designated opf, that we discovered in a genetic screen of fast neutron bombardment mutants in an attempt at floral-dip transformation of Melilotus alba (Fabaceae; white sweetclover), an alternative papilionoid legume host for Sinorhizobium meliloti. The opf mutant developed flowers with reflexed sepals and petals, thereby exposing the stamens and carpel, whereas wild-type sweetclover inflorescences developed closed flowers where the young stamens and carpel remain covered during the early stages of flower development. Based on crosses with the wild type, the mutant segregated as a single, Mendelian recessive. Crosses were successful only when the opf mutant served as the female parent, suggesting that the mutant was male sterile. However, no obvious differences from wild-type stamen development were observed in the opf mutant. The anther defect was due to indehiscence. However, as the plants approached the end of their life cycle, the frequency of selfing increased. We also investigated whether the opf mutant could be transformed via Agrobacterium tumefaciens floral-dip infiltration because open flowers like those of Arabidopsis appear to be more readily transformable. However, similar to wild-type M. alba, the opf mutant is refractory to floral-dip transformation by Agrobacterium tumefaciens.

Allelopathic effect by aqueous extracts of different parts of Croton bonplandianum Baill. on some crop and weed plants

The present study was conducted to investigate the allelopathic effects of Croton bonplandianum weed on seed germination and seedling growth of crop plants (Triticum aestivum L., Brassica oleracea var. botrytis L. and Brassica rapa L.) and weed plants (Melilotus alba Medik., Vicia sativa L. and Medicago hispida Gaertn). Root, stem and leaf aqueous extracts of Croton at 0.5, 1.0, 2.0 and 4.0% concentrations were applied to determine their effect on seed germination and seedling growth of test plants under laboratory conditions. The aqueous extracts from root, stem and leaf had no effect on seed germination of test plants. The extracts from stem had a stimulatory effect on the shoot length at all concentration levels, as against an inhibitory effect of leaf extracts. Stem extracts at low concentration generally promoted root length but aqueous extracts from leaf and root inhibited root length and dry weight. Root length, shoot length of weed species decreased progressively when plants were exposed to increasing concentration (0.5, 1, 2 and 4%). The pH, osmotic potential and total phenolic contents, the osmotic potential and phenolic content increased with increasing concentrations of aqueous extracts of different parts of C. bonplandianum while pH does not have any major change. Key words: Allelopathy, aqueous leaf extract, aqueous stem extract, aqueous root extract, Melilotus alba, Medicago hispida, Vicia sativa, Croton bonplandianum.

Ensifer, Phyllobacterium and Rhizobium species occupy nodules of Medicago sativa (alfalfa) and Melilotus alba (sweet clover) grown at a Canadian site without a history of cultivation

Phage-resistant and -susceptible bacteria from nodules of alfalfa and sweet clover, grown at a site without a known history of cultivation, were identified as diverse genotypes of Ensifer, Rhizobium and Phyllobacterium species based on sequence analysis of ribosomal (16S and 23S rRNA) and protein-encoding (atpD and recA) genes, Southern hybridization/RFLP and a range of phenotypic characteristics. Among phage-resistant bacteria, one genotype of Rhizobium sp. predominated on alfalfa (frequency approximately 68 %) but was recovered infrequently ( approximately 1 %) from sweet clover. A second genotype was isolated infrequently only from alfalfa. These genotypes fixed nitrogen poorly in association with sweet clover and Phaseolus vulgaris, but were moderately effective with alfalfa. They produced a near-neutral reaction on mineral salts agar containing mannitol, which is atypical of the genus Rhizobium. A single isolate of Ensifer sp. and two of Phyllobacterium sp. were recovered only from sweet clover. All were highly resistant to multiple antibiotics. Phylogenetic analysis indicated that Ensifer sp. strain T173 is closely related to, but separate from, the non-symbiotic species 'Sinorhizobium morelense'. Strain T173 is unique in that it possesses a 175 kb symbiotic plasmid and elicits ineffective nodules on alfalfa, sweet clover, Medicago lupulina and Macroptilium atropurpureum. The two Phyllobacterium spp. were non-symbiotic and probably represent bacterial opportunists. Three genotypes of E. meliloti that were symbiotically effective with alfalfa and sweet clover were encountered infrequently. Among phage-susceptible isolates, two genotypes of E. medicae were encountered infrequently and were highly effective with alfalfa, sweet clover and Medicago polymorpha. The ecological and practical implications of the findings are discussed.

Alternative hosts and plant tissues for the survival, sporulation and spread of the Ascochyta blight pathogen of chickpea

Various crop and weed species were infected naturally by Didymella rabiei (anamorph: Ascochyta rabiei) in blight-affected chickpea fields in the Palouse region of eastern Washington and northern Idaho, USA. The fungus was isolated from asymptomatic plants of 16 species commonly found in commercial crops in this region. Isolates of the pathogen from crop and weed species were pathogenic to chickpea and indistinguishable in cultural and morphological characteristics from isolates of D. rabiei from chickpea. Both mating types of D. rabiei were isolated from eight naturally infected plant species. Chickpeas were infected by D. rabiei when plants emerged through infested debris of seven crop and weed species. The teleomorph developed on overwintered tissues of seven plant species infected naturally by D. rabiei in a blight screening nursery and on debris of wheat, white sweet clover and pea inoculated with ascospores of D. rabiei or conidia of two compatible isolates of the pathogen. Didymella rabiei naturally infected 31 accessions of 12 Cicer spp. and the teleomorph developed on the overwintered debris of all accessions, including those of three highly resistant perennial species. The fungus developed on the stem and leaf pieces of ten plant species common to southern Spain inoculated with conidia of two compatible isolates of D. rabiei, and formed pseudothecia with asci and viable ascospores on six of ten species and pycnidia with conidia on all plant species.

Invasive White Sweetclover (Melilotus officinalis) Control with Herbicides, Cutting, and Flaming

AbstractWhite sweetclover is invading the Alaska glacial river floodplains and roadsides adjacent to natural areas, and control methods are needed. Chlorsulfuron, 2,4-DB, clopyralid, triclopyr, and 2,4-D controlled white sweetclover seedlings below recommended rates in the greenhouse. Biomass of established plants in the field was reduced by chlorsulfuron at recommended (17.6 g ai/ha), 1/2, and 1/4 rates and was reduced by triclopyr and 2,4-D at recommended rates (1,260 and 1,600 g ai/ha). Herbicides were more effective at reducing white sweetclover viable seed production in 2007 than in 2006. Only chlorsulfuron at 17.6 g ai/ha (recommended rate) eliminated seed production in both years. Flaming killed first-year plants, but some second-year plants resprouted and produced viable seed. Cutting at the 2.5 or 10 cm height did not control first-year plants because of regrowth, and second-year plant density and seed production was reduced by cutting at 2.5 cm but not by cutting at 10 cm.

Nutrition classics from The Journal of Biological Chemistry 138:21-33, 1941. Studies on the hemorrhagic sweet clover disease. IV. The isolation and crystallization of the hemorrhagic agent by Harold A. Campbell and Karl Paul Link.

1. The hemorrahgic agent is spoiled sweet clover hay (Melilotus alaba) has been isolatd in a pure state, m. p. 288-289°, from experimentally produced spoiled hays as well as form hyas that killed cattle in argicultural practice. 2. This substance has the empirical formula C12H12O6. It is optically inactive. There are two acidic hydroxyls in the molecule. The acidity of the pure substance falls between that of the phenols and the carboxylic acids. A crystalline dimethyl other C12H12O4(OCH2)2 with a melting point fo 168-170° (physiologically inactive) has been prepared by methylation with diazomethane. 3. In the pure state the substance has a low soulubility in the ordinary organic solvents. It is insoluble in acid media. Basic solvenets. and dilute alkali effect solution radily (salt formation). 4. The substance could not be characterized or identified on the basis of its behavior towards the usual identification reagents. Its occurrence in nature has not previosly been reproted. 5. 1.5 mg. of hte crystalline hemorrhagic agent cause approximately the same reduciton in the prothrombin level or activity of the plasma of standardized susceptible reabbits in 40 hours as 50 gm. of the standard spoiled hay sample. 6. Spoiled sweet cover hays produced experimentally from Melilotus alba and those relized in agricultural parctice contain approximately 0.003 per cent of the hemorrhagic agent on the dry substance basis. The over-all yield of the subsance in a fractionation scheme involving sixteen steps approximates 86 per cent of the quantity present.

Comparison of Initial Growth Responses to Water Availability of Two Chinese Desert Dune Species and Nine Cultivated Species

Seed traits and germination responses to water availability can be related to seedling emergence and survival in sand and thus can affect the adaptability of species to desert dune environments. Water absorption by seeds, germination speed, responses of germination to water stress (imposed using polyethylene glycol-6000), and the effects of irrigation on seedling emergence and survival in sand were compared among two desert dune herbs from northeastern China (Astragalus adsurgens and Melilotus albus) and nine cultivated species (lettuce, carrot, turnip, sesame, Welsh onion, radish, cucumber, barley, and snap bean). Seeds that germinated rapidly after irrigation, those that germinated under low water potential, and those with small dry weight tended to produce emergent seedlings in response to a smaller amount of irrigation. However, these seedlings did not survive long, indicating that ready seedling emergence did not always promote seedling establishment. Drought resistance of seedlings was not correlated with seed traits or germination responses. The results indicated that the desert dune species were not less sensitive to water deficiency than the cultivated species at the initial growth stage. This may result from the fact that precipitation occurs predominantly during the summer in the desert dunes of northeastern China. As a result, species tend not to suffer from water deficiency during the initial growth stage.