Effect of Ca~(2+) on Membrane Lipid Peroxidation and Protective Systemes in leaves of Mango Seedlings Under Water Stress
The effects of Ca2+ on membrane lipid peroxidation and protective system were studied in leaves of intact mango seedlings under water stress and in detached leaves after 48 h of PEG osmotic stress. The results indicated that Ca2+ sprayed upon the leaf surface of mango seedlings under water stress obviously slowed down the decreasing of leaves water content, of superoxidase dismutase (SOD) activity and of ascorbic acid (Vc) content. The peroxidase (POD) activity of the leaf surface was increased after spraying and its decreasing rate was hence lessened; the malondialdehyde (MDA) accumulation was reduced evidently. EGTA pretreatment could reduce the effect of Ca2+, and chlorpromazine (cpz) pretreatment inhibited the activities of SOD and POD. It is thought that Ca2+ increased or activated cellular calmodulin (CaM) and then regulated the activities of some relative enzymes, thereby reducing the injury of water stress to the membrane of mango leaves.