Effects of nitric oxide on salt stress tolerance in Kosteletzkya virginica

Salt stress is considered to be a major limiting factor for plant growth and crop productivity. Our previous study showed that exogenous application of sodium nitroprusside ( 60 mu M SNP), a nitric oxide ( NO) donor, could attenuate salt injuries in Kosteletzkya virginica. To further understand such protective roles of NO against salt stress, the effects of exogenous SNP on dry weight, activities of major antioxidant enzymes, proline accumulation, lipid peroxidation and distribution of sodium in K. virginica under salt stress were investigated. Application of SNP can increase dry weight, activities of catalase, peroxidase and superoxide dismutase, proline accumulation and decrease MDA contents in the presence of SNP under salt stress. Treatment with NaCl at 100, 200, 300 and 400 mM and SNP reduced Na+ levels but increased K+ levels in roots and shoots in comparison with the NaCl-treated plants. Correspondingly, the plants treated with exogenous SNP and NaCl maintained a lower ratio of [Na+]/[K+] in NaCl-stressed plants. These data suggest that NO might confer salt tolerance in K. virginica by preventing both oxidative membrane damage and translocation of Na+ from root to shoots. [Life Science Journal. 2009; 6(1): 67 - 75] (ISSN: 1097 - 8135).