Effect of dehulling and germination on the functional properties of grass pea (Lathyrus sativus) flour.

The compositional, bioactive, functional, pasting, and thermal characteristics of native, dehulled, and germinated grass pea flour were examined. Germination significantly improved the protein content and bioactive properties while simultaneously reducing total carbohydrate and fat levels. However, dehulling increased the fat content, foaming, and emulsion properties. Dehulling and germination significantly increased (p < 0.05) the functional properties by improving flowability and cohesiveness. Although processing methods enhance functional properties, the pasting properties of dehulled and germinated flours differ significantly (p < 0.05) from the native flour. The X-ray diffraction patterns indicate a reduction in percentage crystallinity in germinated flours. Overall, the study suggests that the dehulling and germination processes enhanced the quality of grass peas by improving nutritive value and functional attributes.

Spring and autumn phenology in an understory herb are uncorrelated and driven by different factors.

PREMISE: Climate warming has altered the start and end of growing seasons in temperate regions. Ultimately, these changes occur at the individual level, but little is known about how previous seasonal life-history events, temperature, and plant-resource state simultaneously influence the spring and autumn phenology of plant individuals. METHODS: We studied the relationships between the timing of leaf-out and shoot senescence over 3 years in a natural population of the long-lived understory herb Lathyrus vernus and investigated the effects of spring temperature, plant size, reproductive status, and grazing on spring and autumn phenology. RESULTS: The timing of leaf-out and senescence were consistent within individuals among years. Leaf-out and senescence were not correlated with each other within years. Larger plants leafed out and senesced later, and size had no effect on growing season length. Reproductive plants leafed out earlier and had longer growing seasons than nonreproductive plants. Grazing had no detectable effects on phenology. Colder spring temperatures delayed senescence in two of three study years. CONCLUSIONS: The timing of seasonal events, such as leaf-out and senescence in plants can be expressed largely independently within and among seasons and are influenced by different factors. Growing season start and length can often be dependent on plant condition and reproductive status. Knowledge about the drivers of growing season length of individuals is essential to more accurately predict species and community responses to environmental variation.

Phenotypic, stress tolerance, and plant growth promoting characteristics of rhizobial isolates of grass pea.

Grass pea (Lathyrus sativus L.) is widely cultivated for food and feed in some developing countries including Ethiopia. However, due to its overexaggerated neuro-lathyrism alkaloid causing paralysis of limbs, it failed to attract attention of the research community and is one of the most neglected orphan crops in the world. But, the crop is considered an insurance crop by resource-poor farmers due to its strong abiotic stress tolerance and ability to produce high yields when all other crops fail due to unfavorable environmental conditions. This study was aimed at screening rhizobial isolates of grass pea and evaluating their symbiotic nitrogen fixation efficiency and tolerance to abiotic stresses. Fifty rhizobial isolates collected from grass pea nodules were isolated, screened, and characterized based on standard microbiological methods. The rhizobial isolates showed diversity in nodulation, symbiotic nitrogen fixation, and nutrient utilization. The 16S rRNA gene sequencing of 14 rhizobial isolates showed that two of them were identified as Rhizobium leguminosarum and the remaining twelve as Rhizobium species. Based on their overall performance, strains AAUGR-9, AAUGR-11, and AAUGR-14 that performed top and identified as Rhizobium species were recommended for field trials. This study screened and identified effective and competitive rhizobial isolates enriched with high nitrogen-fixing and abiotic stress tolerant traits, which contributes much to the application of microbial inoculants as alternative to chemical fertilizers.

In situ effects of Lathyrus sativus- PGPR to remediate and restore quality and fertility of Pb and Cd polluted soils.

Rehabilitation of heavy metals contaminated soils using association between legumes and beneficial rhizospheric microorganisms such as plant growth-promoting bacteria (PGPR) is a major challenge in agronomy. The present study focuses on assessing the impact of field inoculation with I1 (Rhizobium leguminosarum (M5) + Bacillus simplex + Luteibacter sp. + Variovorax sp.) and I5 (R. leguminosarum (M5) + Pseudomonas fluorescens (K23) + Luteibacter sp. + Variovorax sp.) on growth and phytoremediation potential of Lathyrus sativus plants as well as soil quality and fertility. The experimentation was carried out in mine tailings of northern Tunisia. Obtained Results indicated that the in situ inoculation with I1 and I5 significantly increased the shoots (47% and 22%) and roots dry weights (22% and 29%), as well as nodules number (48% and 31%), respectively, compared to uninoculated plants. The maximum Pb accumulation in the above-ground tissue was recorded in plants inoculated with I5 (1180.85 mg kg-1 DW). At the same time, we noticed a reduction in total Pb and Cd in the rhizosphere of inoculated plots mainly in those inoculated with I5 reaching 46% and 61%, respectively, compared to uninoculated plots. Likewise, I5 inoculum significantly enhanced soil total nitrogen (35%) and available phosphorus (100%), as well as ß-glucosidase (16%), urease (32%) and alkaline phosphatase (12%) activities. Here we demonstrate the usefulness of L. sativus inoculated with I5 inoculum formed by mixing efficient and heavy metals resistant PGPR to boost an efficient reclamation of Cd and Pb contaminated soils and, ultimately, to improve their quality and fertility.

Genotypic and symbiotic diversity of native rhizobia nodulating red pea (Lathyrus cicera L.) in Tunisia.

Nodulation and genetic diversity of native rhizobia nodulating Lathyrus cicera plants grown in 24 cultivated and marginal soils collected from northern and central Tunisia were studied. L. cicera plants were nodulated and showed the presence of native rhizobia in 21 soils. A total of 196 bacterial strains were selected and three different ribotypes were revealed after PCR-RFLP analysis. The sequence analysis of the rrs and two housekeeping genes (recA and thrC) from 36 representative isolates identified Rhizobium laguerreae as the dominant (53%) rhizobia nodulating L. cicera. To the best of our knowledge, this is the first time that this species has been reported among wild populations of the rhizobia-nodulating Lathyrus genus. Twenty-five percent of the isolates were identified as R. leguminosarum and isolates LS11.5, LS11.7 and LS8.8 clustered with Ensifer meliloti. Interestingly, five isolates (LS20.3, LS18.3, LS19.10, LS1.2 and LS21.20) were segregated from R. laguerreae and clustered as a separate clade. These isolates possibly belong to new species. According to nodC and nodA phylogeny, strains of R. laguerreae and R. leguminosarum harbored the symbiotic genes of symbiovar viciae and clustered in three different clades showing heterogeneity within the symbiovar. Strains of E. meliloti harbored symbiotic genes of Clade V and induced inefficient nodules.

Grass pea (Lathyrus sativus L.): orphan crop, nutraceutical or just plain food?

MAIN CONCLUSION: Although grass pea is an environmentally successful robust legume with major traits of interest for food and nutrition security, the genetic potential of this orphan crop has long been neglected. Grass pea (Lathyrus sativus L.) is a Neolithic plant that has survived millennia of cultivation and has spread over three continents. It is a robust legume crop that is considered one of the most resilient to climate changes and to be survival food during drought-triggered famines. The hardy penetrating root system allows the cultivation of grass pea in various soil types, including marginal ones. As an efficient nitrogen fixer, it meets its own nitrogen requirements and positively benefits subsequent crops. However, already in ancient India and Greece, overconsumption of the seeds and a crippling neurological disorder, later coined neurolathyrism, had been linked. Overemphasis of their suspected toxic properties has led to disregard the plant's exceptionally positive agronomic properties and dietary advantages. In normal socio-economic and environmental situations, in which grass pea is part of a balanced diet, neurolathyrism is virtually non-existent. The etiology of neurolathyrism has been oversimplified and the deficiency in methionine in the diet has been overlooked. In view of the global climate change, this very adaptable and nutritious orphan crop deserves more attention. Grass pea can become a wonder crop if the double stigma on its reputation as a toxic plant and as food of the poor can be disregarded. Additionally, recent research has exposed the potential of grass pea as a health-promoting nutraceutical. Development of varieties with an improved balance in essential amino acids and diet may be relevant to enhance the nutritional value without jeopardizing the multiple stress tolerance of this promising crop.

Transcriptome profiling illustrates expression signatures of dehydration tolerance in developing grasspea seedlings.

MAIN CONCLUSION: This study highlights dehydration-mediated temporal changes in physicochemical, transcriptome and metabolome profiles indicating altered gene expression and metabolic shifts, underlying endurance and adaptation to stress tolerance in the marginalized crop, grasspea. Grasspea, often regarded as an orphan legume, is recognized to be fairly tolerant to water-deficit stress. In the present study, 3-week-old grasspea seedlings were subjected to dehydration by withholding water over a period of 144 h. While there were no detectable phenotypic changes in the seedlings till 48 h, the symptoms appeared during 72 h and aggravated upon prolonged dehydration. The physiological responses to water-deficit stress during 72-96 h displayed a decrease in pigments, disruption in membrane integrity and osmotic imbalance. We evaluated the temporal effects of dehydration at the transcriptome and metabolome levels. In total, 5201 genes of various functional classes including transcription factors, cytoplasmic enzymes and structural cell wall proteins, among others, were found to be dehydration-responsive. Further, metabolome profiling revealed 59 dehydration-responsive metabolites including sugar alcohols and amino acids. Despite the lack of genome information of grasspea, the time course of physicochemical and molecular responses suggest a synchronized dehydration response. The cross-species comparison of the transcriptomes and metabolomes with other legumes provides evidence for marked molecular diversity. We propose a hypothetical model that highlights novel biomarkers and explain their relevance in dehydration-response, which would facilitate targeted breeding and aid in commencing crop improvement efforts.

Heavy metal accumulation in Lathyrus sativus growing in contaminated soils and identification of symbiotic resistant bacteria.

In this study, two populations of leguminous plants Lathyrus sativus were grown in four soils that were collected from sites differently contaminated by heavy metals. Evaluations included basic soil properties, concentrations of major nutrients and four metals (copper, zinc, lead and cadmium) in these soils. Investigation of Lathyrus sativus response to contamination showed that the increase of heavy metal concentration in soils affected biomass of plant, number of nodules and plant metal uptake. Heavy metal tolerance of 46 isolated bacteria from the root nodules was evaluated and demonstrated that the maximum concentration of Cd, Pb, Cu and Zn tolerated by strains were 0.8, 2.5, 0.2, and 0.5 mM, respectively. Twenty-two isolates were tested for their effects on plant biomass production and nodule formation and showed that only R. leguminosarum nodulated Lathyrus sativus, while some bacteria improved the shoot and root dry biomass. Sequences of their 16S rDNA gene fragments were also obtained and evaluated for tentative identification of the isolates which revealed different bacterial genera represented by Rhizobium sp, Rhizobium leguminosarum, Sinorhizobium meliloti, Pseudomonas sp, Pseudomonas fluorescens, Luteibacter sp, Variovorax sp, Bacillus simplex and Bacillus megaterium. The existence of Pb- and Cd-resistant genes (PbrA and CadA) in these bacteria was determined by PCR, and it showed high homology with PbrA and CadA genes from other bacteria. The tested resistant population was able to accumulate high concentrations of Pb and Cd in all plant parts and, therefore, can be classified as a strong metal accumulator with suitable potential for phytoremediation of Pb and Cd polluted sites. Heavy metal resistant and efficient bacteria isolated from root nodules were chosen with Lathyrus sativus to form symbiotic associations for eventual bioremediation program, which could be tested to remove pollutants from contaminated sites.

Effect of magnetic field on in vitro seedling growth and shoot regeneration from cotyledon node explants of Lathyrus chrysanthus boiss.

The stimulatory effects on germination of seeds and growth of plants of static magnetic field (MF) pre-treatments depending on MF intensity, exposure time periods, signal form, flux density, and source frequencies on plants are reported. Seed germination frequency is low due to dormancy in Lathyrus chrysanthus Boiss. from Fabaceae family, consisting of 187 taxa. Tissue culture protocol for this plant has already been optimized. This plant is also used as a model for developing alternative methods to overcome dormancy. This study was conducted to determine the effects of MF on in vitro seed germination, seedling growth, and shoot regeneration capacity of cotyledon node explants in Lathyrus chrysanthus Boiss. to obtain healthy seedlings in large quantities. The seeds of an ecotype (Diyarbakir) were subjected to 125 mT MF strength for different exposure time periods (0-untreated, 24, 48, and 72 h). Sterilized seeds were germinated on growth basal medium in Magenta vessels. Seed germination and seedling growth percentages were recorded after 7 and 14 days of culture initiation, whereas seedling and root lengths were noted 28 days after culture initiation. At the end of the culture, shoot regeneration percentage, shoot number per explant, highest shoot height per explant, and total shoot number per petri dish were recorded. According to the results, it could be concluded that MF treatment could clearly be used to improve germination by breaking dormancy not only in Lathyrus chrysanthus Boiss. but also other plant species. Bioelectromagnetics. 39:547-555, 2018.© 2018 Wiley Periodicals, Inc.

Potential of efficient and resistant plant growth-promoting rhizobacteria in lead uptake and plant defence stimulation in Lathyrus sativus under lead stress.

The ability of plant growth-promoting rhizobacteria (PGPR) to enhance Lathyrus sativus tolerance to lead (Pb) stress was investigated. Ten consortia formed by mixing four efficient and Pb-resistant PGPR strains were assessed for their beneficial effect in improving Pb (0.5 mM) uptake and in inducing the host defence system of L. sativus under hydroponic conditions based on various physiological and biochemical parameters. Lead stress significantly decreased shoot (SDW) and root (RDW) dry weight, but PGPR inoculation improved both dry weights, with highest increases in SDW and RDW of plants inoculated with I5 (R. leguminosarum (M5) + P. fluorescens (K23) + Luteibacter sp. + Variovorax sp.) and I9 (R. leguminosarum (M5) + Variovorax sp. + Luteibacter sp. + S. meliloti) by 151% and 94%, respectively. Additionally, inoculation significantly enhanced both chlorophyll and soluble sugar content, mainly in I5 inoculated leaves by 238% and 71%, respectively, despite the fact that Pb decreased these parameters. We also found that PGPR inoculation helps to reduce oxidative damage and enhances antioxidant enzyme activity, phenolic compound biosynthesis, carotenoids and proline content. PGPR inoculation increased Pb uptake in L. sativus, with highest increase in shoots of plants inoculated with I5 and I7, and in roots and nodules of plants inoculated with I1. Moreover, PGPR inoculation enhanced mineral homeostasis for Ca, Cu and Zn under Pb stress, mainly in plants inoculated with I1, I5, I7 and I9. Results of our study suggest the potential of efficient and Pb-resistant PGPR in alleviating harmful effects of metal stress via activation of various defence mechanisms and enhancing Pb uptake that promotes tolerance of L. sativus to Pb stress.

Tissue specific expression and in-silico characterization of a putative cysteine synthase gene from Lathyrus sativus L.

Grass pea (Lathyrus sativus L.) is a worldwide popular pulse crop especially for its protein rich seeds with least production cost. However, the use of the crop became controversial due to the presence of non-protein amino acid, ß-N-oxalyl-L-α, ß-diaminopropionic acid (ß-ODAP) in its seed and leaf, which is known as the principle neurotoxin to cause neurolathyrism (a motor neurodegenerative disease of humans and animals) during prolonged consumption as regular diet. Till date, the knowledge on ß-ODAP biosynthesis in Lathyrus sp. is limited only to a small part of the complex bio-chemical steps involved including a few known sulfur-containing enzymes (viz. cysteine synthase, ODAP synthase etc.). In Lathyrus sativus, biosynthesis of ß-ODAP varies differentially in a tissue-specific manner as well as in response to several environmental stresses viz. zinc deficiency, iron over-exposure, moisture stress etc. In the present study, a novel cysteine synthase gene (LsCSase) from Lathyrus sativus L was identified and characterized through bioinformatics approaches. The bioinformatic analysis revealed that LsCSase showed maximum similarity with the O-acetyl serine (thiol) lyase of Medicago truncatula with respect to several significant sequence-specific conserved motifs (cysK, CBS like, ADH_zinc_N, PALP), sub-cellular localization (chloroplast or cytoplasm) etc., similar to other members of cysteine synthase protein family. Moreover, the tissue-specific regulation of the LsCSase as well as its transcriptional activation under certain previously reported stressed conditions (low Zn+2-high Fe+2, PEG induced osmotic stress) were also documented through quantitative real-time PCR analyses, suggesting a possible link between the LsCSase gene activation and ß-ODAP biosynthesis to manage external stresses in grass pea. This preliminary study offers a probable way towards the development of less toxic consumer-safe grass pea by down-regulation or deactivation of such gene/s (cysteine synthase) through genetic manipulations.

Reducing anti-nutritional factor and enhancing yield with advancing time of planting and zinc application in grasspea in Ethiopia.

BACKGROUND: Grasspea (Lathyrus sativus L.) is an important pulse crop for food, feed and sustainable crop production systems in Ethiopia. Despite its advantages in nutrition and adaptability to harsh climate and low fertile soil, it contains a neurotoxin, ß-N-oxalyl-α,ß-diamiono propionic acid (ß-ODAP), which paralyses the lower limbs and is affected by genotypic and agronomic factors. To determine the effect of zinc application and planting date on yield and ß-ODAP content of two genotypes, experiments were conducted in two regions of Ethiopia. RESULTS: The main effects of variety, sowing date and zinc and their interactions were significant (P < 0.001) for ß-ODAP and seed yield, which had a linear relationship with zinc. For the improved grasspea variety, an application of 20 kg ha-1 zinc showed a reduction of ß-ODAP from 0.15% to 0.088% at Debre Zeit and 0.14% to 0.08% at Sheno and increased its yield from 841 kg ha-1 to 2260 kg ha-1 at Debre Zeit and from 715 to 1835 kg ha-1 at Sheno. Early sowing showed a reduction in ODAP content in relation to the late sowing. CONCLUSION: An application of Zn beyond even 20 kg ha-1 with an early sowing is recommended for the improved variety. © 2017 Society of Chemical Industry.

Metabolomics Approach To Understand Mechanisms of ß-N-Oxalyl-l-α,ß-diaminopropionic Acid (ß-ODAP) Biosynthesis in Grass Pea (Lathyrus sativus L.).

A study was performed to identify metabolic processes associated with ß-ODAP synthesis in grass pea using a metabolomics approach. GC-MS metabolomics was performed on seedlings at 2, 6, and 25 days after sowing. A total of 141 metabolites were detected among the three time points representing much of grass pea primary metabolism, including amino acids, carbohydrates, purines, and others. Principal component analysis revealed unique metabolite profiles of grass pea tissues among the three time points. Fold change, hierarchical clustering, and orthogonal projections to latent structures-discriminant analyses, and biochemical pathway ontologies were used to characterize covariance of metabolites with ß-ODAP content. The data indicates that alanine and nitrogen metabolism, cysteine and sulfur metabolism, and purine, pyrimidine, and pyridine metabolism were associated with ß-ODAP metabolism. Our results reveal the metabolite profiles in grass pea development and provide insights into mechanisms of ß-ODAP accumulation and degradation.

Genotypic Variation in the Concentration of ß-N-Oxalyl-L-α,ß-diaminopropionic Acid (ß-ODAP) in Grass Pea (Lathyrus sativus L.) Seeds Is Associated with an Accumulation of Leaf and Pod ß-ODAP during Vegetative and Reproductive Stages at Three Levels of Water Stress.

Grass pea (Lathyrus sativus L.) cultivation is limited because of the presence in seeds and tissues of the nonprotein amino acid ß-N-oxalyl-L-α,ß-diaminopropionic acid (ß-ODAP), a neurotoxin that can cause lathyrism in humans. Seven grass pea genotypes differing in seed ß-ODAP concentration were grown in pots at three levels of water availability to follow changes in the concentration and amount of ß-ODAP in leaves and pods and seeds. The concentration and amount of ß-ODAP decreased in leaves in early reproductive development and in pods as they matured, while water stress increased ß-ODAP concentration in leaves and pods at these stages. The net amount of ß-ODAP in leaves and pods at early podding was positively associated with seed ß-ODAP concentration at maturity. We conclude that variation among genotypes in seed ß-ODAP concentration results from variation in net accumulation of ß-ODAP in leaves and pods during vegetative and early reproductive development.

Local environment and density-dependent feedbacks determine population growth in a forest herb.

Linking spatial variation in environmental factors to variation in demographic rates is essential for a mechanistic understanding of the dynamics of populations. However, we still know relatively little about such links, partly because feedbacks via intraspecific density make them difficult to observe in natural populations. We conducted a detailed field study and investigated simultaneous effects of environmental factors and the intraspecific density of individuals on the demography of the herb Lathyrus vernus. In regression models of vital rates we identified effects associated with spring shade on survival and growth, while density was negatively correlated with these vital rates. Density was also negatively correlated with average individual size in the study plots, which is consistent with self-thinning. In addition, average plant sizes were larger than predicted by density in plots that were less shaded by the tree canopy, indicating an environmentally determined carrying capacity. A size-structured integral projection model based on the vital rate regressions revealed that the identified effects of shade and density were strong enough to produce differences in stable population sizes similar to those observed in the field. The results illustrate how the local environment can determine dynamics of populations and that intraspecific density may have to be more carefully considered in studies of plant demography and population viability analyses of threatened species. We conclude that demographic approaches incorporating information about both density and key environmental factors are powerful tools for understanding the processes that interact to determine population dynamics and abundances.

Homoarginine, ß-ODAP, and asparagine contents of grass pea landraces cultivated in Turkey.

The seeds of grass pea (Lathyrus sativus L.), a drought tolerant crop, were analysed for quantitative determination of the free amino acids ß-N-oxalyl-l-α,ß-diaminopropionic acid (ß-ODAP), homoarginine and asparagine by a simple and fast capillary electrophoretic method. In boric acid (80mM, pH 8.0) running buffer system, not only were α and ß-ODAP successfully separated, but also an efficient sample stacking was achieved during hydrodynamic sample introduction. The validated method was used for quantification of ß-ODAP, homoarginine and asparagine in seed extracts of 52 Lathyrus local landraces from various regions of Turkey and one released cultivar. The concentration ranges of amino acids were found as 0.21-1.27% (w/w) for homoarginine, 0.10-0.87% (w/w) for ß-ODAP and 0.006-0.47% (w/w) for asparagine. A positive correlation between homoarginine and ß-ODAP quantities in seeds of 53 Lathyrus local landraces was shown to exist (r(2)=0.649).

Systematics, biogeography, and character evolution of the legume tribe Fabeae with special focus on the middle-Atlantic island lineages.

BACKGROUND: Tribe Fabeae comprises about 380 legume species, including some of the most ancient and important crops like lentil, pea, and broad bean. Breeding efforts in legume crops rely on a detailed knowledge of closest wild relatives and geographic origin. Relationships within the tribe, however, are incompletely known and previous molecular results conflicted with the traditional morphology-based classification. Here we analyse the systematics, biogeography, and character evolution in the tribe based on plastid and nuclear DNA sequences. RESULTS: Phylogenetic analyses including c. 70% of the species in the tribe show that the genera Vicia and Lathyrus in their current circumscription are not monophyletic: Pisum and Vavilovia are nested in Lathyrus, the genus Lens is nested in Vicia. A small, well-supported clade including Vicia hirsuta, V. sylvatica, and some Mediterranean endemics, is the sister group to all remaining species in the tribe. Fabeae originated in the East Mediterranean region in the Miocene (23-16 million years ago (Ma)) and spread at least 39 times into Eurasia, seven times to the Americas, twice to tropical Africa and four times to Macaronesia. Broad bean (V. faba) and its sister V. paucijuga originated in Asia and might be sister to V. oroboides. Lentil (Lens culinaris ssp. culinaris) is of Mediterranean origin and together with eight very close relatives forms a clade that is nested in the core Vicia, where it evolved c. 14 Ma. The Pisum clade is nested in Lathyrus in a grade with the Mediterranean L. gloeosperma, L. neurolobus, and L. nissolia. The extinct Azorean endemic V. dennesiana belongs in section Cracca and is nested among Mediterranean species. According to our ancestral character state reconstruction results, ancestors of Fabeae had a basic chromosome number of 2n=14, an annual life form, and evenly hairy, dorsiventrally compressed styles. CONCLUSIONS: Fabeae evolved in the Eastern Mediterranean in the middle Miocene and spread from there across Eurasia, into Tropical Africa, and at least seven times to the Americas. The middle-Atlantic islands were colonized four times but apparently did not serve as stepping-stones for Atlantic crossings. Long-distance dispersal events are relatively common in Fabeae (seven per ten million years). Current generic and infrageneric circumscriptions in Fabeae do not reflect monophyletic groups and should be revised. Suggestions for generic level delimitation are offered.

Flower power: its association with bee power and floral functional morphology in papilionate legumes.

BACKGROUND AND AIMS: A test was made of the hypothesis that papilionate legume flowers filter pollinators according to their ability to exert strength to open flowers to access rewards. In addition, interactions with pollen vectors were expected to explain the structural complexity of the architecture of these flowers since operative flower strength may be determined by a combination of morphological traits which form part of an intrafloral functional module. METHODS: Six papilionate species were studied: Collaea argentina, Desmodium uncinatum, Galactia latisiliqua, Lathyrus odoratus, Spartium junceum and Tipuana tipu. Measurements were made of the strength needed to open keels and the strength that pollinators were capable of exerting. Morphological traits of all petals were also measured to determine which of them could be either mutually correlated or correlated with operative strength and moment of strength and participated in a functional module. KEY RESULTS: It was observed that pollinators were capable in all cases of exerting forces higher and often several times higher than that needed to access floral rewards, and no association could be detected between floral operative strength and strength exerted by the corresponding pollinators. On the other hand, strong and significant correlations were found among morphometric traits and, of these, with operative strength and moment. This was particularly evident among traits of the keel and the wings, presumably involved in the functioning of the floral moveable mechanism. CONCLUSIONS: Though visitors are often many times stronger than the operative strength of the flowers they pollinate, exceptionally weak bees such as Apis mellifera cannot open the strongest flowers. On the other hand, strong correlations among certain petal morphometric traits (particularly between the keel and wings) give support to the idea that an intrafloral module is associated with the functioning of the mechanism of these legume flowers. In addition, the highly significant correlations found across petals support the view of functional phenotypic integration transcending the ontogenetic organization of flower structure.

Environmental effect on yield, composition and technological seed traits of some Italian ecotypes of grass pea (Lathyrus sativus L.).

BACKGROUND: Grass pea seeds are a good source of vegetable proteins, but the presence of toxic and antinutritional compounds represents a barrier to their large-scale use as food or animal feed. How much growing location and/or seasonal climate might affect the storage of these factors has been little investigated. RESULTS: Fourteen Italian ecotypes of grass pea were cultivated in two locations in southern Italy characterised by different climatic conditions. The seven ecotypes with the best yields and/or seed quality were investigated for a further two growing seasons. From a statistical point of view the physicochemical and nutritional traits among ecotypes were not the same from one year to the next. Moreover, a significant positive correlation was found between ß-oxalyl-diamino-propionic acid and trypsin inhibitor contents. The lowest levels of both these compounds were associated with the highest amount of rainfall during the plant vegetative cycle. CONCLUSION: Principal component analysis of the data showed that the overall seed composition was affected by the growing location. Consequently, each grass pea genotype should also be carefully investigated in relation to different environments before being considered for release as safe for widespread human or animal consumption.

Factors affecting ß-ODAP content in Lathyrus sativus and their possible physiological mechanisms.

A neuroexcitatory non-protein amino acid, ß-N-oxalyl-L-α,ß-diaminopropionic acid (ß-ODAP), present in the seeds of the hardy legume crop grass pea (Lathyrus sativus L.), was considered responsible for human lathyrism. The levels of ß-ODAP were reported to vary in different tissues during plant development, and to be affected by a wide range of environmental stresses. In this paper, dynamic changes in ß-ODAP level at specific stages of plant development as well as the influences of various environmental factors, including nutrient deficiency, drought, salinity, toxic heavy metals, and Rhizobium symbiosis on ß-ODAP levels were analyzed, highlighting the relationship between changes in ß-ODAP concentrations and Rhizobium growth. Possible mechanisms underlying ß-ODAP accumulation are proposed and future research is suggested.