乙酰水杨酸对镍胁迫下水稻幼苗中O2^—水平和膜脂过氧化的影响

Effects of Acetosalicylic Acid on Levels of Superoxide Anion and Peroxidation of Membrane Lipid in Rice Seedlings Under Nickel Stress

采用室内培养及生理指标测定方法，研究了乙酰水杨酸对镍胁迫下水稻幼苗中部分生理指标的影响。结果表明， 10 μ mol· L－ 1和 30 μ mol· L－ 1的镍胁迫下，稻苗叶片中 SOD活性明显降低，质外体中的 NADH氧化酶活性显著上升；同时，细胞中总和质外体中产生明显加快，从而导致叶片组织中 MDA含量和质膜透性亦明显增加。同样胁迫条件下，加入 0.05％ ASA， SOD活性回升，产生速率回落， MDA含量和质膜透性增加的程度亦减小，但乙酰水杨酸 (ASA)对质外体中 NADH氧化酶活性无明显影响。这些结果提示产生与积累导致的膜脂过氧化作用介导了镍对稻苗的毒害； ASA能降低产生速率，减轻膜脂过氧化损伤程度。

Two stress concentrations of nickel tested (10,30μ mol· L－ 1) significantly decreased superoxide dismutase (SOD) activity in rice leaves, while enhanced NADH oxidase activity significantly in apoplast. Measurement of, malondialdehyde(MDA), relative electric conductivity showed that there was a significantly increase in both totalgeneration rate and that of apoplast, as well as in MDA content and the plasma membrane permeability after nickel treatment. Addition of 0.05％ acetylsalicylic (ASA) to the same nickel stress condition decreased the rate of decline in SOD activity, and that of increase in generation, MDA content and the plasma permeability observed in rice leaves treated with nickel alone. However, no changes in apoplast NADH oxidase activity were observed. The results suggested that accumulation and membrane lipid peroxidation were involved in the toxicity to rice seedlings led by nickel, and the decline in level and membrane lipid peroxidation were the reasons by which ASA mitigated the injuries induced by nickel stress in rice seedlings.