小麦叶片在干旱条件下的膜损伤与脂质过氧化

MEMBRANE INJURY AND LIPID PEROXIDATION IN WHEAT LEAVES UNDER DROUGHT

随干旱强度的加剧，用传统方法测得的小麦叶片中ＴＢＡＲＳ的含量不断增加；但在排除了糖类物质干扰后，ＴＢＡＲＳ含量却随干旱强度的增加而稍有下降。脂质氢过氧化物含量及乙烷释放速率在处理间无明显差异、干旱刺激生成的同时促进了ＳＯＤ、ＣＡＴ及ＧＲ的活性。干旱条件下小麦叶片膜透性的增加与脂质过氧化无直接联系。

The effect of drought on the membrane lipid peroxidation in winter wheat leaveswas investigated and the activities of superoxide dismutase(SOD). glutpthionereductase(GR) and catalase(CAT) were also analyzed. After 10 days of treatment. droughtstress resulted in a decrease in the leaf water potential and an increase in the membranepermeability.Thiobarbituric acid reacting substances(TBARS).a widely used index of membrane lipid peroxidation,estimated according to Heath and Packer (1968). increasedmarkedly in responce to drought stress. But this estimation obviously suffered from the interference of soluble sugars in wheat leaves.as showed by the absorption spestra ofTBARS. This interference could be overcome by calculating the TBA values(△OD)as follows: COD=OD532-(ODs510+OD560)/ 2. We found that such calculated TBARS decreased slightly with the increase of drought stress. Other indices of lipid peroxidation suchas lipid hydroperoxide content and ethane production remained unchanged in all treatments. Drought stress stimulated the production of and enhanced the activities of SOD.GR and CAT in wheat leaves. According to these results. we conclude that lipidperoxidation may not be a primaly cause of drought injury to cell membrane in plant tissues.