Assessment of antioxidant enzymes activity and peroxidation of membrane lipid in cowpea (Vigna unguiculata L.) genotypes under normal and drought stress condition

Understanding the physiological processes associated with drought stress lead to an understanding of the basic mechanisms of resistance, maintaining yield potential and contribute to the identification of drought tolerant cultivars. For this purpose, the effects of drought stress in cowpea genotypes was evaluated using five different genotypes with different yield potential in a pot experiment in split plot in a randomized complete block design with three replications under drought stress levels (35, 65 and 100% of field capacity) in the College of Agriculture, University of Tehran in 2014. Drought stress decreased RWC of cells and increase antioxidant enzyme and MDA content. Drought stress decreased RWC and increase MDA content and antioxidant enzyme activities by increasing levels of stress, but for catalase enzyme in stress levels the highest activity was 65%. With increasing stress and the stress level of 35% of field capacity, catalase activity exhibited higher reduction. Genotypes 210 and 313 had the lowest MDA level at 35% of field capacity and in these two genotypes enzymes CAT, GPX and APX 210 had the highest value. High levels of antioxidant enzyme activity in genotypes 210 and 291 associated with lower levels of MDA content in these genotypes, probably indicates the high potential of these genotypes to eliminate oxygen species production and yield stability compared with other genotypes.