外源NO对野生早熟禾幼苗抗寒性的影响

以野生草地早熟禾（Poa pratensis）和硬质早熟禾（Poa sphondylodes）为材料，通过人工室内模拟低温逆境胁迫，研究外源一氧化氮（NO）供体亚硝基铁氰化钠（硝普钠，SNP）对低温胁迫下野生早熟禾幼苗生长、渗透调节和抗氧化系统的影响，探讨外源NO提高早熟禾抗寒性的生理机制。结果表明，低温胁迫下：0~700 μmol·L^-1浓度范围内，随SNP浓度的增大，两个供试材料的地上生物量和生长速度先增大后减小，相对膜透性、丙二醛（MDA）含量、游离脯氨酸（F-Pro）含量先减小后增大，可溶性糖（SS）和可溶性蛋白（SP）含量先增加后减小，超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性先增强后减弱；高浓度NO产生伤害，低浓度NO则有保护作用；SNP浓度100 μmol·L^-1时，膜脂过氧化水平最低，渗透调节物质积累最多，保护酶活性最强，对低温胁迫的缓解效果最佳。硬质早熟禾对低温胁迫下外源NO的缓解较草地早熟禾敏感。

Effect of NO on Cold Resistance of Several Wild Kentucky Bluegrass Germplasm Materials

In order to explore the physiological mechanism of exogenous NO to improve the cold resistance of Poa effects of exogenous nitric oxide (NO) donor sodium nitroprusside (SNP) on growth, osmotic adjustment and antioxidant system of seedlings of Poa under low temperature stress which was simulated by artificial turf on wild Poa pratensis and Poa sphondylodes were studied. Results showed that with the SNP concentration increasing, the aboveground biomass, growth rate, the content of soluble sugar (SS) and soluble protein (SP), the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of the two tested materials first increased and then decreased in the concentration range of sodium nitroprusside which was 0-700 mol·L^-1 under the low temperature stress. The relative membrane permeability, the content of malondialdehyde (MDA) and free proline (Pro) trended conversely. It was harmful in high concentration of NO while low concentration of NO had a protective effect. Among all the NO experimental treatments, 100 μmol·^-1 showed the best alleviation effect on cold-resistance, the lowest level of membrane lipid peroxidation, accumulated the greatest amount of osmotic regulation substances, and the highest activity of active-oxygen-scavenging enzyme. The alleviation of exogenous NO in P. sphondylodes Trin. was more sensitive than that of Poa pratensis. under low temperature stress.