Effect of soil water on protective enzyme activity and membrane lipid peroxidation in pea

A pot experiment was conducted to investigate the effect of soil water on protective enzymes of superoxide dismutase(SOD),catalase(CAT) and peroxidase(POD),and also on membrane lipid peroxidation including malonaldehyde(MDA) and plasma membrane permeability(RC) in pea(Pisum sativum Linn.) leaf during flowering and pod-bearing stages under drought stress and water recovery conditions.Antioxidant ability of pea during flowering and pod-bearing stages was also analyzed.The results indicate that SOD and CAT activity is not significantly influenced by 5-day drought stress with only obvious time lag,but signifi-cantly decreases under 10-day drought stress condition.Leaf MDA content increases significantly under 10-day high drought stress.POD activity and leaf RC increase under drought stress.Water recovery has a considerable compensation effect on CAT and POD activity,but also leads to over-compensation effect on SOD activity.Meanwhile MAD content and RC level decrease notably.Pea has strong oxidation resistance within 10 days of drought stress and water recovery.The resistance capacity decreases only under 10-day severe drought stress and water recovery.