【作者】 黎峥；

【导师】 武宝玕；

【作者基本信息】 暨南大学 ， 水生生物学， 2003， 硕士

【摘要】 UV-B辐射增强可引起深远的环境问题，藻类具有相应的适应机制，却存在种类间的差异。本文对五种藻进行短时和较长时间的UV-B辐射处理，研究不同藻类的生理生化响应。结果表明这五种藻类抗UV-B的能力大小的顺序为：钝顶螺旋藻＞微绿球藻＞纤细角刺藻＞海洋原甲藻＞球形棕囊藻。 UV的增强可破坏叶绿素a，使其含量下降。钝顶螺旋藻和微绿球藻中在较低的UV辐射强度下类胡萝卜素含量升高，而叶绿素a保持相对稳定，说明类胡萝卜素可能对藻类起到一定保护作用，可能通过直接的或间接的方式猝灭激发态的叶绿素，来保障光合作用的进行；本实验发现多糖的累积和分泌与藻体的抗UV能力有相关，钝顶螺旋藻的细胞内和细胞外多糖分泌旺盛，其抗UV能力最强；微绿球藻体内能积累多糖，而胞外多糖分泌减少；球形棕囊藻的胞内多糖含量减少，胞外多糖含量增加也不明显，其抗UV能力最弱。同时实验中还发现钝顶螺旋藻在较长时间UV-B处理下没有明显的细胞损伤，这为藻类多糖的生产提供了一个新思路。另外这三种藻类分泌到细胞外的物质的紫外吸收情况对于不同藻类有所不同。本文推测UV-B辐射的变化可能是影响赤潮发生的诱因之一。更多还原

【Abstract】 UV-B radiation enhancement can cause many environmental problems. Algae have different mechanisms to adapt UV-B enhancement. In this study, 5 algae were chosen as experimental materials, their physiological and biochemical responses were studied under both short time and longer period of UV-B treatment. Results showed that these algae have different ability in resisting UV-B enhancement: Spirulina plalensis >Nanochloropsis sp>Chaetoceros gracilis> Proroceatrum micans >Phaeocystis globosa scherffel.UV can destroy Ch1a, making Ch1a content decrease. Carotenoids content increased in algae Spirulina plalensis and Nanochloropsis sp under lower dosage of UV-B treatment. The result proved that Carotenoids maybe play important roles in photoprotection of algae. Carotenoids can make Chla return from excited state to ground state by direct or un-direct quenching, in order to prevent algae from photooxidation. On the other hand, it was indicated that polysaccharides have functions in resisting UV. Spirulina plalensis can accumulate both cellular and extracellular polysaccharides during UV treatment, it showed highest UV resistant ability; Nanochloropsis sp also can accumulate cellular polysaccharides, while extracellular polysaccharides reduced; the cellular polysaccharides content of Phaeocystis globosa scherffel decreased and extracellular polysaccharides content did not increased markedly, showing lowest UV resistant ability. Spirulina plalensis showed no cellular damage during the longer period of UV-B enhancement treatment, that may provide a new way for polysaccharides production. From results, we can presume that UV-B enhancement may be one of factors, which cause red tide. When weather changes, causing UV-B decreased, some UV-susceptible algae would become dominant, it grow fast and eventually resulting in red tide formation.更多还原