外源一氧化氮对铅胁迫下小麦种子萌发及幼苗生理特性的影响

利用室内水培实验，研究了外源一氧化氮（NO）供体硝普钠（SNP）对Pb²⁺处理下小麦（Triticum aestivum L.）种子萌发、幼苗生长及相关生理指标变化的影响。结果表明，Pb²⁺处理使小麦种子发芽势、发芽率、幼苗根长和茎长均显著降低，诱导叶绿素a、叶绿素b含量减少及叶绿素荧光参数F_v/F_m和F_v/F_o的比值减小，25 μmol·L^-1 SNP明显缓解Pb²⁺胁迫对种子萌发及幼苗生长的抑制作用，提高Pb²⁺胁迫下叶绿素a、叶绿素b含量及F_v/F_m和F_v/F_o的比值，而100 μmol·L^-1SNP无明显缓解作用。此外，25和100 μmol·L^-1SNP诱导Pb²⁺胁迫下小麦幼苗叶片过氧化氢酶（CAT）活性增强和可溶性蛋白含量增多，但100 μmol·L^-1SNP处理降低了过氧化物酶（POD）活性。结果说明，外源NO促进Pb²⁺胁迫下小麦种子萌发及幼苗生长，提高叶绿素和可溶性蛋白含量，诱导CAT活性升高，从而增强小麦对Pb²⁺胁迫的适应性。

Effects of Exogenous Nitric Oxide on Seed Germination and Physiological Characteristics of Wheat Seedlings under Lead Stress

By the method of solution culture, wheat was used to investigate the effects of exogenous NO donor SNP on seed germination and seedlings physiological characteristics under Pb²⁺ stress. The results showed that Pb²⁺ treatment resulted in significant decreases in seed germination and seedling growth of wheat，and notable reduction in the levels of chlorophyll a, chlorophyll b and chlorophyll fluorescence, 25 μmol·L^-1 SNP could alleviate the inhibition of Pb²⁺ on these indexes. No significant changes in the activities of CAT and POD were observed in comparison with the control under Pb²⁺ stress. However, the application of SNP induced increases of CAT activity and soluble protein content in wheat seedlings under Pb²⁺ treatment. Therefore, exogenous NO could alleviate the poison of Pb²⁺ and enhance the adaptation of wheat seedlings to Pb²⁺ stress.