中文摘要：

为探明NO对缓解植物Cd毒害的生理机制,研究了在30 mg/L Cd^2＋胁迫下,外源施加不同浓度一氧化氮供体硝普钠（SNP）对水稻幼苗生长、膜脂过氧化以及活性氧代谢相关酶活性的影响。结果表明,SNP处理可以不同程度缓解Cd胁迫对水稻幼苗生长的抑制,降低了幼苗根和叶片中H2O2和丙二醛（MDA）的含量,减轻了氧化性损伤,降低了Cd胁迫下水稻幼苗根和叶片中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、愈创木酚过氧化酶（GPX）、抗坏血酸过氧化物酶（APX）等抗氧化相关酶的活性;NO在植物体内的作用对浓度具有依赖性,低浓度NO可以作为一个有效的活性氧清除剂来降低氧化胁迫,但是作为一个活性很强的自由基,较高浓度NO又能够引起氧化胁迫。

英文摘要：

The growth of rice seedling,membrane lipid peroxidation and the specific activities of antioxidant enzymes（superoxide dismutase,catalase,ascorbate peroxidase and guaiacol peroxidase） in rice seedlings treated with a varying concentrations of SNP under 30 mg/L Cd^2＋ stress were evaluated.The results showed that pretreatment with SNP alleviated significantly the oxidative damage caused by Cd stress in the leaves and roots of rice seedlings,reduced the contents of H2O2 and malondialdehyde（MDA）,and decreased the activities of superoxide dismutase（SOD）,catalase（CAT）,ascorbate peroxidase（APX）,and guaiacol peroxidase（GPX） in the leaves and roots of rice seedlings under Cd stress.Nitric Oxide（NO） acted in plants with a concentration-dependent manner,lower concentrations of NO acting as an efficient scavenger in breaking the oxidative chain.Higher NO concentrations could provoke a major oxidative insult,since this molecule is a nitrogen reactive species.