Ca^(2+)对水分胁迫条件下芒果叶片膜脂过氧化及膜保护系统的影响

Effect of Ca^(2+) on Membrane Lipid Peroxidation and Protective Systemes in leaves of Mango Seedlings Under Water Stress

以芒果幼苗为材料，研究Ｃａ２＋对水分胁迫条件下，叶片膜脂过氧化和膜保护系统的效应。结果表明：与对照叶片相比，涂施Ｃａ２＋后，叶片含水量、超氧化物歧化酶（ＳＯＤ）活性及Ｖｃ含量下降明显减慢；过氧化物酶（ＰＯＤ）活性上升加快且幅度加大，而下降延迟；丙二醛（ＭＤＡ）积累显著减少。Ｃａ２＋专一性螯合剂ＥＧＴＡ可削弱Ｃａ２＋的效应。ＣａＭ 拮抗剂氯丙嗪（ＣＰＺ）对叶片ＳＯＤ活性和ＰＯＤ活性有抑制作用，推测Ｃａ２＋可能通过与ＣａＭ结合调节相关酶活性，从而减轻水分胁迫对膜的伤害。

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.