花生幼苗对UV-B辐射增强的生理生化响应

Physiological and Biochemical Responses of Arachis hypogaea Seedlings to Enhanced UV-B

以"小京生"花生幼苗为材料,通过大田栽培试验,旨在探明花生对增强的UV-B辐射(54μW/cm2)响应的生理生化机制.结果表明:在补增UV-B辐射处理下,叶片相对电导率,超氧阴离子(O·-2)、类黄酮和可溶性蛋白质的含量,以及过氧化氢酶(CAT)、过氧化物酶(POD)活性较对照显著升高;超氧化物歧化酶(SOD)活性先显著升高后降低;过氧化氢(H2O2)、丙二醛(MDA)、抗坏血酸(AsA)和谷胱甘肽(GSH)含量,以及抗坏血酸过氧化物酶(APX)活性没有显著变化.可见增强的UV-B能显著提高花生叶片内的活性氧(ROS),O·-2是对花生产生氧化胁迫的主要因素,花生幼苗主要通过提高类黄酮含量以及SOD,CAT和POD活性来抵制ROS的胁迫,AsA-GSH循环系统在花生清除ROS中效果不明显.

A field experiment was conducted to explore the physiological and biochemical mechanisms of the responses of the seedlings of peanut （A rachis hypogaea L.） cv .Xiaojingsheng to enhanced UV-B radiation （54 μW/cm2 ） .In the treatment of supplementary ultraviolet-B （UV-B） ,the contents of superoxide anion （O·2^- ）,flavonoidsandsolubleproteins ,theactivitiesofcatalase （CAT）andperoxidase（POD）and the relative electrical conductivity in the peanut leaves were increased significantly ,the activity of superoxide dismutase （SOD） increased at first and then decreased ;nevertheless ,the contents of hydrogen perox-ide （H2O2） ,malondialdehyde （MDA） ,ascorbic acid （AsA） and glutathione （GSH） and the activities of ascorbate peroxidase （APX） showed no significant changes in the leaves .These results indicated that elevated UV-B could significantly increase the content of reactive oxygen species （ROS） in peanut leaves , O·2^- was the principal factor for oxidative stress ,and peanut seedlings resisted the stress of ROS mainly through increasing the content flavonoids and the activities of SOD ,CAT and POD ,and that the AsA-GSH circulatory system had no obvious effect on clearing ROS .