外源NO对NaCl胁迫下黄瓜幼苗生长和根系谷胱甘肽抗氧化酶系统的影响

以津春2号黄瓜为材料,采用营养液水培的方法,研究了外源一氧化氮(NO)对黄瓜幼苗生长和根系谷胱甘肽抗氧化酶系统的影响.结果表明,(1)正常生长条件下添加NO能促进黄瓜幼苗生长,而添加亚甲基蓝(MB-1)显著抑制黄瓜幼苗的生长;(2)添加NO显著缓解了NaCl胁迫对黄瓜幼苗生长的抑制,提高根系还原型谷胱甘肽(GSH)含量、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性,而氧化型谷胱甘肽(GSSG)含量略有下降,同时缓解了NaCl胁迫下抗坏血酸(ASA)含量的下降幅度;(3)NaCl胁迫下添加NO的同时添加MB-1可部分解除NO的作用,与NaCl胁迫下单独添加NO处理比较,GR活性、GSH和ASA含量均降低,GSSG含量提高,APX先升高后下降.研究发现,外源NO可能通过鸟苷酸环化酶(cGC)介导来调节NaCl胁迫下黄瓜幼苗根系GR活性和GSH、GSSG、ASA含量,提高抗氧化酶活性和非酶抗氧化物质含量,增强植株对活性氧的清除能力,减少膜脂过氧化,缓解NaCl胁迫对黄瓜幼苗造成的伤害.

Effects of Exogenous Nitric Oxide on Growth and Glutathione Dependent Antioxidative System in Cucumber Seedling Roots under NaCl Stress

The study was conducted in nutrient solution to investigate the effects of exogenous nitric oxide(NO) on growth and glutathione dependent antioxidative system in cucumber seedling roots and found out NO enhancing salt-resistant characteristic which lay further foundation for plant physiological mechanisms.The results showed that exogenous nitric oxide increased the growth of cucumber seedling in normal growth conditions.But a nitric scavenger,methylene blue(MB-1),blocked the effects of nitric oxide,markedly decreased the growth of cucumber seedling.Exogenous nitric oxide increased the activity of GR,APX and content of GSH,ASA,decreased the content of GSSG under NaCl stress.But MB-1 blocked some effects of exogenous nitric oxide under NaCl stress,such as decreased activity of GR,the content of GSH,ASA.So all that suggested NO might adjust the activity of GR and the content of GSH,GSSG,ASA through cGC.Increase of antioxidative enzymes activity and content of non-enzyme antioxitant substance improved the ability of eliminating reactive oxygen species and reducing lipid peroxidation.Thersfore,nitric oxide could alleviate the injury of cucumber seedlings from NaCl stress.