Genotypic Variation in the Concentration of β-N-Oxalyl-L-α,β-diaminopropionic Acid (β-ODAP) in Grass Pea (Lathyrus sativus L.) Seeds Is Associated with an Accumulation of Leaf and Pod β-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 beta-N-oxalyl-L-alpha,beta-diaminopropionic acid (beta-ODAP), a neurotoxin that can cause lathyrism in humans. Seven grass pea genotypes differing in seed beta-ODAP concentration were grown in pots at three levels of water availability to follow changes in the concentration and amount of beta-ODAP in leaves and pods and seeds. The concentration and amount of beta-ODAP decreased in leaves in early reproductive development and in pods as they matured, while water stress increased beta-ODAP concentration in leaves and pods at these stages. The net amount of beta-ODAP in leaves and pods at early podding was positively associated with seed beta-ODAP concentration at maturity. We conclude that variation among genotypes in seed beta-ODAP concentration results from variation in net accumulation of beta-ODAP in leaves and pods during vegetative and early reproductive development.