水分胁迫对白三叶叶片脂质过氧化作用及保护酶活性的影响

目的]研究白三叶幼苗在水分胁迫下O2-.产生和由O2-.引发的膜脂过氧化对细胞的伤害,以及超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）的变化。方法]以海发（Trifolium repens.cv.Haifa）（抗旱性强）和瑞文德（Trifolium repens.cv.Rivendel）（抗旱性差）为供试白三叶品种,通过测定膜相对透性和酶活性研究了干旱胁迫对白三叶的影响。结果]在重度干旱胁迫下,2个供试品种叶片的膜相对透性均显著增加,海发叶片的膜相对透性增加较少;海发叶片的丙二醛（MDA）含量在初期显著增加,瑞文德叶片的MDA含量增加极显著;海发叶片的CAT活性在后期显著增加,瑞文德叶片的CAT活性呈显著下降的趋势。在轻度干旱胁迫下,瑞文德叶片的MDA含量增加显著;瑞文德叶片的CAT活性呈显著下降的趋势。结论]该研究为白三叶育种和早期选择提供了科学依据和生理生化指标。

Effects of Water Stress on Lipid Peroxidation and Protective Enzyme Activities in White Clover Leaves

Objective] The purpose was to study the producing of O-2· in young white clover seedlings under water stress,the damage of membrane lipid peroxidation induced by O-2· on cells and the changes of superoxide dismutase,catalase and peroxydase. Method] With Trifolium repens. cv. Haifa with high strong resistance and Trifolium repens. cv. Rivendel with weak drought resistance as tested white clover varieties,the effects of drought stress on white clover were studied through determining the relative permeability of membrane and enzyme activities. Result] Under heavy drought stress,the relative permeability of membrane of the 2 tested varieties was increased significantly and that of Haifa leaf was increased less; the MDA content in Haifa leaf was increased significantly in early stage and that in Rivendel leaf was increased extremely significantly; the CAT activity in Haifa leaf was increased significantly in late stage and that in Rivendel leaf showed significant decreasing trend. Under light drought stress,the MDA content in Rivendel leaf was increased significantly and its CAT activity showed significant decreasing trend. Conclusion] This study supplied scientific basis and physiological and biochemical indexes for breeding and early selection of white clover.