外源一氧化氮供体硝普钠浸种对盐胁迫下小麦幼苗碳氮代谢及抗氧化系统的影响

预先用0.1mmol/L的SNP(硝普钠,NO供体)浸种,研究NO预处理对120mmol/L NaCl胁迫下两小麦品种(扬麦12和淮麦17)幼苗叶片抗氧化系统、碳氮代谢及蛋白酶活性的影响。结果表明,NO预处理能有效地抑制NaCl胁迫下小麦幼苗叶片超氧阴离子释放(O.2-)和过氧化氢(H2O2)积累,提高超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,降低丙二醛(MDA)含量,提高叶绿素、类胡萝卜素和可溶性总糖含量。另外,NO预处理显著提高叶片可溶性蛋白质含量,以及内肽酶和羧肽酶活性。分析表明,NO有利于维持盐胁迫下小麦碳氮代谢正常运转,从而促进植株生长,提高小麦幼苗株高、鲜重和干重。试验条件下,NO对淮麦17的促进作用大于扬麦12。

Effects nitroprusside, a nitric oxide donor,on carbon and nitrogen metabolism and the activity of the antioxidation system in wheat seedings under salt stress

Seeds of two wheat cultivars (Huaimai and Yangmai) were pre-soaked with 0.1 mmol/L SNP (sodium nitroprusside, a nitric oxide donor) to study the effects of nitric oxide (NO) on the activity of the antioxidation system, carbon and nitrogen metabolism, and activities of proteinase in wheat seedlings growing with 120 mmol L-1 NaCl. Exogenous NO significantly reduced the O-?2(superoxide anion) release rate as well as H2O2 content. The activities of SOD (superoxide dismutase) and CAT (catalase)increased, which resulted in a decrease in malondialdehyde (MDA) content in leaves of the seedlings growing under salt stress. In addition, exogenous NO increased the contents of chlorophyll, carotenoids, and the total soluble sugars. Compared with the salt stress treatment alone, the NO pre-treatment significantly increased the content of soluble protein and enhanced the activities of both endopeptidase and carboxypeptidase in leaves. Thus, NO effectively contributed to a better balance between carbon and nitrogen metabolism in seedlings growing under salt stress, and this pre-treatment increased growth rates, as increases in plant height, fresh and dry weight were observed. In addition, Huaimai 17 was more responsive to exogenous NO than Yangmai 12 in this study.