螺旋藻对短期增强UV-B辐射的生理生化响应  

Physiological and biochemical responses of Spirulina platensis to short-term enhanced UV-B radiation

作　　者：薛林贵[1] 石小霞[1] 褚可成[1] 陈志梅[1] 李师翁[1] 

机构地区：[1]兰州交通大学化学与生物工程学院,甘肃兰州730070

出　　处：《中国水产科学》2011年第5期1108-1114,共7页Journal of Fishery Sciences of China

基　　金：国家自然科学基金项目(3087038430960063);甘肃省科技支撑计划项目(090NKCA079)

摘　　要：通过生物化学和对比分析的方法,研究了短期增强UV-B辐射对钝顶螺旋藻(Spirulina platensis)794光合色素、丙二醛(MDA)、类菌孢素氨基酸(MAAs)以及脯氨酸含量的影响。研究结果显示,与未经过UV-B辐射处理的藻细胞相比,增强的UV-B(240μW/cm2)辐射可导致藻细胞叶绿素a和类胡萝卜素以及藻胆蛋白含量下降,以及MDA含量显著变化(P<0.05),表明螺旋藻对UV-B辐射敏感,UV-B辐射对藻细胞光合色素具有抑制和破坏作用,对螺旋藻的膜系统也产生重要影响。而UV-B辐射可导致MAAs含量增加,脯氨酸含量随辐射时间的延长而提高,说明增强UV-B辐照能诱导藻细胞屏蔽色素合成以及抗逆物质脯氨酸的累积,这可能是螺旋藻对UV-B胁迫所做出的适应性反应。The amount of UV-B radiation reaching the earth＇s surface is increasing due to attenuation of the stratospheric ozone.Although the release of ozone-depleting material has declined significantly in the past decade,there is a considerable lag in the recovery of the ozone layer.Cyanobacteria are the oldest photosynthetic pro-karyotes and play an important role in the aquatic ecosystem.UV-B can penetrate water to a depth sufficient to disrupt aquatic ecosystems.For example,the depth of water required to remove 90% of the solar radiation at 310 nm is about 20 m in the clearest ocean.Thus,a large number of cyanobacteria populate aquatic habitats that are exposed to UV-B radiation.UV-B radiation is known to affect cyanobacteria biomass by disrupting physiological and biochemical processes.However,cyanobacteria have developed mechanisms to counteract the damaging ef-fects of UV-B,including production of UV-screening pigments [（e.g.,mycosporine-like amino acids（MAAs）] and downward migration.We evaluated the effects of short-term enhanced UV-B radiation on physiological indices,including photosynthetic pigment content,MDA,MAAs,and proline,in Spirulina platensis.S.platensis were exposed to 240 μW/cm2 UV-B for 3.5 h.By compared with untreated cyanobacteria cells,exposure to increased levels of UV-B radiation was associated with a reduction in chlorophyll a,carotenoid and phycobiliprotein content,with a change in MDA content.Our results suggest that increased levels of UV-B radiation causes bleaching of the photosynthetic pigment.Exposure to higher levels of UV-B was also associated with increased synthesis of MAAs and accumulation of proline.We hypothesize that this is a mitigation strategy to reduce the damaging effects of UV-B.

关 键 词：螺旋藻 UV-B 光合色素 MDA 脯氨酸 MAAS 

分 类 号：X171[环境科学与工程—环境科学]