外源一氧化氮对盐胁迫下黑麦草幼苗生长及生理特性的影响

研究了外源一氧化氮（nitric oxide,NO）对盐胁迫下多年生黑麦草幼苗生长及相关生理指标变化的影响。结果表明,与对照相比,50～200μmol·L-1NO供体硝普钠（sodium nitroprusside,SNP）可缓解盐胁迫对黑麦草幼苗生长的抑制作用,其中100μmo·lL-1SNP缓解作用最强。外施SNP显著缓解了盐胁迫导致的叶片相对电导率、K＋与Na＋比率、丙二醛含量和活性氧水平的增加,提高了盐胁迫下幼苗叶子中脯氨酸含量和超氧化物歧化酶、过氧化氢酶、抗坏血酸过氧化物酶和过氧化物酶等抗氧化酶的活性。这些结果说明,NO可能通过降低细胞吸收Na＋的量、增加细胞吸收K＋的量和脯氨酸含量以及激活抗氧化保护酶等减轻了盐对黑麦草的伤害,提高了黑麦草的抗盐性。

Effects of exogenous nitric oxide on growth and physiological characteristics of ryegrass seedlings under salt stress

Effects of exogenous nitric oxide (NO) on growth and changes in some physiological characteristics of perennial ryegrass seedlings under salt stress were investigated. The results indicated that exogenous NO donor, named sodium nitroprusside (SNP), at concentrations of 50-200 mol L-1 obviously alleviated the inhibition of salt upon the ryegrass seedling growth in comparison with the control; and 100 mol L-1 SNP had the strongest effects. Furthermore, treatments of the seedlings with SNP resulted in the pronounced alleviation in the increases of relative electrolyte leakage, K+ to Na+ ratio, the content of malondialdehyde and levels of reactive oxygen species in leaves under salt stress compared with the control. In addition, SNP treatments markedly enhanced the proline content and the activities of the main antioxidant enzymes superoxide dismutase, catalase, ascorbate peroxidase and peroxidase in leaves of the seedlings under salt stress. These findings suggest that NO may alleviate the damage caused by salt in ryegrass seedlings via decreasing the Na+ content, increasing the contents of K+ and proline, and activating the antioxidant protest enzymes, thus improves salt resistance of the perennial ryegrass plants.