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草业学报 ›› 2017, Vol. 26 ›› Issue (4): 178-187.DOI: 10.11686/cyxb2016190

• 研究论文 • 上一篇    下一篇

一氧化氮参与调节PEG渗透胁迫下白三叶抗氧化酶活性及其基因表达

吴星, 王晓娟, 彭燕*   

  1. 四川农业大学动物科技学院草业科学系,四川 成都 611130
  • 收稿日期:2016-05-09 出版日期:2017-04-20 发布日期:2017-04-20
  • 作者简介:吴星(1992-),女,四川南充人,在读硕士。E-mail:wuxings2015@163.com
  • 基金资助:
    国家自然科学基金(31372371)和四川省支撑项目(2013NZ0013)资助

Nitric oxide is involved in regulating antioxidant enzyme activity and expression of their encoding genes in white clover under PEG osmotic stress

WU Xing, WANG Xiao-Juan, PENG Yan*   

  1. College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China
  • Received:2016-05-09 Online:2017-04-20 Published:2017-04-20

摘要: 以 ‘拉丁诺’ 白三叶为材料,采用药理学实验,研究15%PEG-6000渗透胁迫下,离体叶片内源NO荧光产生及NO含量动态变化,NO清除剂及合成抑制剂对白三叶叶片抗氧化酶活性及其基因表达量的影响以及外源NO供体(SNP)对渗透胁迫的缓解效应。渗透胁迫可诱导白三叶叶片NO荧光产生,NO含量升高,提高抗氧化酶活性,上调抗氧化酶基因表达水平,而Hb、NR、NaVO3和L-NAME则显著抑制了胁迫诱导的NO含量、抗氧化酶活性及其基因表达水平的提升;外源根施50 μmol/L SNP促进了胁迫下叶片抗氧化酶活性的提高,并有效减缓了相对含水量的下降,抑制电解质渗透率(EL)和MDA含量的升高。以上结果表明,NO是白三叶响应渗透胁迫的重要信号分子,并可能通过调控氧化酶基因表达和提高抗氧化酶活性,以减轻渗透胁迫对白三叶幼苗的过氧化伤害。

Abstract: The aim of this study was to evaluate the role of endogenous nitric oxide (NO) in regulating antioxidant enzyme activity in white clover (Trifolium repens cv. Ladino) under osmotic stress. We investigated endogenous NO fluorescence, dynamic changes in NO content, antioxidant enzyme activity, and the transcript levels of genes encoding antioxidant enzymes in white clover treated with an NO scavenger or NO synthesis inhibitors, and also evaluated the mitigating effects of the exogenous NO donor, sodium nitroprusside (SNP). Leaves of white clover were subjected to osmotic stress (15% PEG-6000). Compared with the leaves in the control, those in the osmotic stress treatment showed higher NO-dependent fluorescence, increased NO content, enhanced activity of antioxidant enzymes, and higher transcript levels of genes encoding antioxidant enzymes. Under osmotic stress, bovine hemoglobin (Hb), sodium vanadate (NaVO3), and LNG-nitro-L-arginine methyl ester hydrochloride (L-NAME) inhibited the accumulation of NO, leading to inhibition of antioxidant enzyme activity and reduced transcript levels of their encoding genes. The NO donor SNP (50 μmol/L) significantly alleviated the decline in the relative water content (RWC), reduced electrolyte leakage, decreased malondialdehyde accumulation, and promoted antioxidant enzyme activities under osmotic stress. These results suggested that NO is an important signaling molecule in response to osmotic stress, and that it plays a role in regulating gene expression and antioxidant enzyme activity to reduce peroxidation injury in white clover.