一氧化氮在光延缓小麦叶片衰老中的作用

The Role of Nitric Oxide in Light-inhibited Senescence of Wheat Leaves

以小麦(Triticum aestivum L.)离体叶片为材料,采用药理学实验和激光扫描共聚焦显微镜技术,对内源一氧化氮(NO)在光延缓离体小麦叶片衰老过程中的作用进行了研究.结果显示:光照处理的同时添加NO清除剂血红蛋白(Hb)或硝酸还原酶抑制剂钨酸钠(Na2WO4)后,光抑制离体小麦叶片叶绿素和可溶性蛋白含量降低及丙二醛累积的效应均显著减弱;光照处理下小麦叶片硝酸还原酶活性和内源NO水平均明显高于黑暗条件下,而Na2WO4处理不仅能抑制光诱导的硝酸还原酶活性提高,还与Hb处理一样能显著降低光下叶片内源NO水平.结果表明,硝酸还原酶途径来源的NO参与了光抑制离体小麦叶片衰老的过程.

By pharmacological experiments combined with laser-scanning confocal microscopy, the role and enzymic source of nitric oxide （NO） in light-inhibited senescence of the detached wheat （Triticurn aestivurn L. ） leaves were studied. Compared to light treatment alone, the treatment of light combined with the NO scavenger hemoglobin （Hb） or nitrate reductase （NR） inhibitor sodium tungstate （Na2WO4） reduced the contents of chlorophyll and soluble protein, and increased lipid peroxidation as quantified by measurement of malondialdehyde. Compared to dark treatment,light treatment also increased NR activity and the level of endogenous NO in the detached wheat leaves. However,when wheat leaves were treated with Na2WO4 un- der light, not only the effect of light on NR activity was inhibited, hut also the effect of light on endogenous NO level was reduced, which was similar to the effect of Hb on endogenous NO level. These results indicate that NR-dependent NO production might be involved in the light-inhibited senescence of the detached wheat leaves.