[Exogenous nitric oxide alleviates osmotic stress-induced membrane lipid peroxidation in wheat seedling leaves]

When wheat (Triticum aestivum L. Yangmai 158) seedling (with three fully expanded leaves) roots were treated with 15% PEG-6000 in combination with different concentrations (0.1 and 0.5 mmol/L) of exogenous nitric oxide donor sodium nitroprusside (SNP) and NO(-)(3)/NO(-)(2) (control), the enhancement of lipoxygenase (LOX) activity in wheat seedling leaves under osmotic stress was delayed at the lower concentration of SNP treatment (0.1 mmol/L), while the generation rate of O(-.)(2), the enhancement of membrane permeability and the accumulation of MDA and H(2)O(2)were also alleviated. SNP 0.1 mmol/L significantly enhanced the activity of superoxide dismutase (SOD), and accelerated the accumulation of proline. In comparison with these changes, the effects of higher concentration of SNP (0.5 mmol/L) and corresponding control (NO(-)(3)/NO(-)(2)) were not so obvious. The above results indicate that lower concentrations of in vitro nitric oxide (NO) can protect wheat seedling leaves from membrane lipid peroxidation caused by osmotic stress.