紫外线-B辐射增强对葡萄叶片抗氧化系统的影响

Effect of enhanced Ultraviolet-B radiation on antioxidant systems in grapevine seedling leaves

【目的】为葡萄UV-B辐射的适应机制研究及抗紫外线品种的选育提供科学依据。【方法】在室外自然光的基础上，用0μW／cm^2（CK）、10．8μW／cm^2（T1）、25．6μW／cm。（T2）3种强度紫外线-B（UV-B，280～320nm）辐射处理葡萄植株30d，研究UV-B辐射增强对葡萄叶片抗氧化系统的影响。【结果】在整个辐射处理期间，T1处理叶片的超氧化物歧化酶（SOD）活性总体高于CK，T2处理叶片的SOD活性较CK有先升高后降低的变化趋势；T1和T2处理葡萄叶片的过氧化氢酶（CAT）活性均呈不断降低的变化趋势，过氧化物酶（POD）活性呈现出先升高后降低再升高的变化趋势。UV-B辐射处理组（T1和T2）类胡萝卜素（Car）含量在辐射初期（6～12d）均低于CK，且差异不显著，但在辐射第30天显著高于CK。T1处理与CK抗坏血酸（ASA）含量均呈逐渐升高的趋势；在辐射初期（6～9d），T2处理ASA含量低于CK，随着辐射量的累积，其ASA含量逐渐升高，24d后呈下降趋势。随着辐射时间的延长，叶片中丙二醛（MDA）的含量明显增加，且始终为T2〉T1〉CK。UV-B辐射处理30d后，CAT、POD活性升高，Car、MDA含量增加，ASA含量降低，而SOD活性变化不大。【结论】UV-B辐射增强对葡萄叶片的抗氧化系统产生了影响，这可能是在UV—B辐射下活性氧的积累引起的。

[Objective] The study was done to reveal the changes of antioxidant systems in grapevine seedling leaves and to provide supports for the investigation of the adaption mechanism of grapevine to UV- B radiation and selection of anti-ultraviolet varieties. [Method] On the basis of the natural light of the out- door,the changes of antioxidant systems in grapevine seedling leaves exposed to three radiations of 0μW/cm2 （CK）, 10.8 μW/cm2 （T1） and 25. 6μW/cm2 （T2） of ultraviolet-B radiation （UV-B, 280 to 320 nm） were studied. [Result] The activities of SOD were higher than that of CK except for the 24 days under T1 treatment; under the treatment of T2, the earlier changes of SOD activation was strengthened,and its activities were weakened with the radiated time lengthened. During the whole treatment, the activities of CAT gradually decreased in the order of TI〉T2〉CK. The activities of POD were heightened at the first 12 days under T1 treatment, and began to reduce till the radiation of 18 days, subsequently, its activities turned to elevate all through ; under T2 treatment,POD activity was remarkably increased,and the highest relative content presented at the radiation of 18 days was 243.33% compared with CK. Relative contents of Car were less than that of CK at the earlier stage of radiation and no significant difference. But the contents were significantly higher than that of CK eventually. The contents of ASA gradually increased under T1 radiation,and the same with CK;its contents were lower than that of CK at the earlier stage of T2 radiation, however,with the increase of accumulation,ASA contents were more than that of CK and its relative con- tents gradually decreased. The MDA contents of the treatments noticeably increased with the accumulating of radiation,and always in the order of T2〉T1〉CK. After accumulative radiation of 30 days,the CAT and POD activities tended to increase, the contents of Car and MDA elevated, the reverse was true in ASA. The activities of SOD almost remained constant. [Conclusion] The analysis indicates that the accumulation of Reactive Oxygen Species （ROS） induced by UV-B radiation may influence the biosynthesis of antioxidant systems.