Studies on the changes in lipid peroxidation and antioxidants in drought stress induced cowpea (Vigna unguiculata L.) varieties.

Cowpea (Vigna unguiculata L.) is one of the major vegetable crops cultivated in tropical conditions. Two varieties of cowpea, i.e., Vigna unguiculata L.cv Kanakamony and cv Pusakomal were selected for the present study. The changes in lipid peroxidation, ascorbic acid content and activities of enzymatic antioxidants associated with drought stress were determined. A high level of lipid peroxidation was observed in test plants subjected to water stress. The Pusakomal leaves with severe stress showed 2.7 fold increase in TBARS compared to control and 1.2 fold to that of Kanakamony The drought tolerant variety showed significant increase in the activities of peroxidase and catalase on exposure to drought stress. Kanakamony leaves in severe stress possess 1.09 times increase in peroxidase and 1.8 times increase in catalase activity than Pusakomal. The concentration of ascorbic acid in test plants depleted with increased drought stress in both varieties. While the leaves of tolerant variety in severe stress showed 1.13 times higher ascorbic acid content than Pusakomal. Among the two varieties, Kanakamony possess the best antioxidant system to tolerate drought stress. This could limit cellular damage caused by active oxygen species, during waterdeficit. The variety Pusakomal was relatively poor in these adaptations.