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