UV-B辐射对蚕豆叶片气孔运动的间接效应与NO和H2O2有关

0.2 W.m-2的UV-B辐射不仅能诱导整体蚕豆叶片气孔导度和开度的显著降低,而且能明显降低蚕豆叶肉光合活性,但该强度的UV-B辐射却不能明显影响离体表皮条的气孔开度.说明0.2W.m-2的UV-B主要通过间接途径调控了蚕豆叶片气孔运动.借助药理学试验和激光扫描共聚焦显微镜技术,进一步对该间接效应过程中是否有NO和H2O2的参与进行了探讨.结果显示:NO专一性清除剂cPT IO和一氧化氮合酶(NO S)抑制剂L-NAM E均能有效地抑制UV-B辐射诱导的叶片气孔关闭和保卫细胞内源NO水平的升高;H2O2清除剂抗坏血酸(A SC)和过氧化氢酶(CAT)也能有效地逆转UV-B辐射诱导的气孔关闭和保卫细胞内源H2O2含量的升高.另外,外源NO或H2O2处理也能有效地诱导叶片气孔关闭.结果说明0.2W.m-2的UV-B辐射对蚕豆叶片气孔关闭的间接诱导与NO和H2O2有关.

Relationship of Indirect Effects of UV-B Radiation on Stomatal Movement of Vicia faba Leaves with Nitric Oxide and Hydrogen Peroxide

0.2 W · m-2 UV-B radiation could induce Vicia faba leaves to not only significantly reduce their stomatal conductance and aperture as a whole but also significantly decrease photosynthetic activity of their leaf mesophyll,but this radiation could not exert significant influence on the stomatal aperture of excised epidermis strips. This indicated that 0. 2 W · m-2 UV-B ratiation adjusted the stomatal movement of V. faba leaves mainly in indirect ways. Whether NO and H2O2 were concerned with the adjustment in indirect ways was further explored by pharmaceutical experiment and laser-scanning confocal microscopy. The results showed that cPTIO,a scavenger specific to No,and L-NAME,NO-synthase inhibitor,both effectively inhibited the closedown of the leaf stomata and the increase of endogenous NO in the guard cells,which were induced by UV-B radiation;ascorbic acid ,a H2O2 in the guard cells ,which were induced by UV-B radiation. In addition,exogenous NO or H2O2 could effectively induce the closedown of the leaf stomata. It was indicated that the indirect induction of 0.2 W · m-2 UV-B radiation to the stomatal closedown of V. faba leaves related to NO and H2O2.