中文摘要：

一氧化氮（nitric oxide,NO）是植物中一种重要的信号分子,在诱导种子萌发,影响植物生长发育,促进植物细胞衰亡等方面发挥着重要作用。然而对于外源NO是否参与了Se诱导的脂质过氧化调节过程仍不为人知。我们研究了0.2μmol L-1和20μmol L-1 Na2SeO3及一氧化氮供体硝普钠（sodium nitroprusside,SNP）处理对水稻叶片叶绿素、H2O2和硫代巴比妥酸反应产物（thiobarbituric acid reactive substances,TBARS）含量,愈创木酚过氧化物酶（guaiacol peroxidase,GPX）、超氧化物歧化酶（superoxide dismutase,SOD）、过氧化氢酶（catalase,CAT）以及抗坏血酸过氧化物酶（ascorbate peroxidase,APX）活性等生理生化指标的影响。结果表明,1μmol L-1 SNP处理促进GPX、APX和CAT活性,缓解膜脂过氧化,降低TBARS含量;显著提高0.2μmol L-1 Na2SeO3处理下水稻叶片中叶绿素含量。在20μmol L-1 Na2SeO3处理下,外加1μmol L-1 SNP更加显著促进GPX和CAT活性,与此同时明显降低20μmol L-1 Na2SeO3处理引起的H2O2含量上升,并降低TBARS含量。NO对植物中由Se引起的脂质过氧化具有调节作用。

英文摘要：

Nitric oxide（NO） is a bioactive molecule that has been suggested to act as a signaling molecular in plants.It induces germination,affects plant growth and development,and promotes plant cell death.NO is also involved in plant response to heat,salinity,ultraviolet-B,and heavy metal stresses.It is known that some effects of NO may relate to the regulation of reactive oxy-gen species（ROS） metabolism by means of affecting activities of catalase（CAT） with hemachrome iron,and/or guaiacol peroxi-dase（GPX） with none-hemachrome iron.However,whether NO regulates lipid peroxidation in rice seedlings induced by selenium is not yet understood.In this article,we reported some regulative effects of exogenous nitric oxide donor SNP on oxidative stresses induced by selenium in rice seedlings.The contents of chlorophyll,H2O2,TBARS and the activities of GPX,superoxide dismutase（SOD）,CAT and ascorbate peroxidase（APX） in rice seedlings treated with a varying concentrations of selenium and 1 μmol L-1 SNP were investigated.The results showed that the content of chlorophyll increased by treatment with SNP in 0.2 μmol L-1 Na2SeO3 group.SNP alleviated significantly the lipid peroxidation in rice seedlings via promoting GPX,APX and CAT activi-ties in rice leaf.In 20 μmol L-1 Na2SeO3 treated rice seedlings,SNP alleviated significantly TBARS content and the increase of H2O2 content that resulted from high selenium stress via promoting GPX,especially APX and CAT activities.Taken together,our results suggested that NO regulates lipid peroxidation caused by selenium in rice seedlings.