钙对烟草叶片热激忍耐和活性氧代谢的影响

Effect of Calcium on the Heat Tolerance and Active Oxygen Metabolism of Tobacco Leaves

热胁迫导致烟草叶片细胞膜系统显著受损 ,表现为SOD活性降低和MDA含量明显升高 ,叶片叶绿素含量下降 ,活性氧增加。 1 0mmol/LCaCl2 溶液处理烟草幼苗后 ,能有效降低热胁迫下叶片细胞膜透性 ,维持较高的SOD和CAT等抗氧化酶活性 ,减缓O- ·2 形成和膜脂过氧化反应。研究结果表明 ,CaCl2 处理提高了烟草叶片膜稳定性和膜保护酶活性 ,有利于保护细胞膜结构 ,降低高温对烟草幼苗的伤害。钙离子螯合剂EGTA能在一定程度上降低烟草叶片的抗热性。

Effects of calcium on the heat tolerance and active oxygen metabolism of tobacco seedling leaves were studied under heat stress. The results indicated that the cell membrane was damaged in leaves and the content of MDA and active oxygen increased, but the activity of SOD and the content of chlorophyll reduced by heat stress. After seedlings were treated with 10 mmol/L CaCl 2 solution, the permeability of cell membrane, membrane_lipid peroxidation and O -· 2 production rate in the tobacco leaves reduced effectively. The activity of antioxidant enzyme such as SOD, POD and CAT in the leaves were still higher than that of the control seedlings.The results suggested that the increased stability of membranes and protective enzyme activities of tobacco leaves by Ca 2+ would favour to protect cell membrane structure. EGTA, the chelating agent of Ca 2+ , could partly decrease heat tolerance of tobacco leaves.