荒漠念珠藻对UV-B辐射的反应及外源抗氧化剂的保护作用  

Response of Nostoc sp.to UV-B Radiation and the Protective Effect of Exogenous Antioxidants to Nostoc sp.

作　　者：邓松强[1] 杨翠琨 安晓亮 胡超珍[1] 陈兰洲[1] 

机构地区：[1]武汉大学资源与环境科学学院,湖北武汉430072 [2]达拉特旗国营白土梁农场,内蒙古达拉特旗014300 [3]内蒙古自治区林业科学研究院,内蒙古呼和浩特010020

出　　处：《干旱区研究》2012年第5期816-819,共4页Arid Zone Research

基　　金：武汉市科技晨光计划项目(200850731367);国家自然科学基金(30970446;30500068)资助

摘　　要：通过分析UV-B辐射对荒漠结皮中的藻类———Nostoc sp.生物学效应的影响,以及外源抗氧化剂对UV-B辐射下藻类的保护作用。结果表明:Nostoc sp.的光合活性(Fv/Fm)随紫外处理强度的增大和处理时间的延长而显著降低,叶绿素荧光产量和相应光合参数(ET0/ABS、ET0/TR0和RC/CS0)降低,活性氧ROS(reactive oxygen evolu-tion)产量显著增加,光合活性降低。而外源抗坏血酸(ASA)和半胱氨酸(NAC)的加入,可以显著提高紫外辐射条件下藻体的光合活性,降低ROS含量,从而有效保护藻类,且抗坏血酸的效果要优于半胱氨酸。实验结果表明:处于藻类结皮上层的Nostoc sp.有较强的对UV-B辐射的抗性,而外源抗氧化剂可以有效保护藻体免受紫外辐射的伤害。In this paper, the effects of UV-B radiation on the physiological and biochemical processes of Nostoc sp. , one of cyanobacteria isolated from desert algal crust, were investigated, and the protective effects of ascorbie acid and N-acetyl-L-cysteine were researched. The results show that the PSII activity （Fv/Fm） of stressed cells was significantly decreased with the increase of irradiance time and intensity, the chlorophyll fluorescence transits and photosynthetic parameters （ETo/ABS,ETo/TRo and RC/CSo ） were also decreased significantly, hut the ROS generation was increased. Exogenous 0. 5 mM aseorbic acid or N-aeetyl-L-cysteine could significantly decrease the production of ROS （reactive oxygen evolution）, and the protective effect of ascorbic acid was better than that of N- acetyl-L-cysteine. The results suggested that Nostoc sp. adapted to the detrimental UV environment in desert, and exogenous antioxidant could effectively protect cells from UV-B damage.

关 键 词：UV辐射 荒漠 生物结皮 蓝藻 光合活性 活性氧 

分 类 号：S154[农业科学—土壤学]