drought stress-induced changes at physiological and biochemical levels in some common vetch (vicia sativa l.) genotypes

common vetch ( vicia sativa l.) an annual forage, belonging to the fabaceae family is one of the highly cultivated forage legumes in iran. drought stress is a serious adverse factor that limits plant growth and productivity, inducing a range of physiological as well as biochemical responses in plants. it may also lead to generation of oxygen activated species which in turn result in cell destruction. in this study, physiological and biochemical responses of six common vetch genotypes to two levels of drought stress (30 and 10% left of fc) were investigated at their early growth stages. results indicate that drought stress significantly affects the relative water content (rwc), electro leakage (el), photosynthetic pigments, and total carotenoids. the obtained results indicated drought induced changes in the activities of such antioxidant enzymes as catalase, glutathione peroxidase and ascorbate peroxidase. there was also found a reverse relationship between catalase and ascorbate peroxidase activities in the studied genotypes. obtained results clearly show that there are highly genotype-dependent responses to drought stress at biochemical level in common vetch genotypes, with each genotype responding to stress in a genotype-specific manner. these results may be helpful in breeding programs related to drought stress resistance.