中文摘要：

采用显微观察和PCR—DGGE2种方法分析太湖（河口、梅梁湾湾心、湖湾交汇处和湖心）4个代表性区域微囊藻群落的季节变化，研究太湖中微囊藻群落的季节变化规律。显微形态分析未发现微囊藻属的主要优势种铜绿微囊藻（Microcystis aeruginosa）、惠氏微囊藻（Microcystis wesenbergii）和水华微囊藻（Microcystis flos—aquae）存在明显的季节变化规律（P〉0．05）。DGGE条带测序结果的亲缘分析表明，太湖夏季和冬季样品中的微囊藻彼此分离成2大特征类群，而春季和秋季样品中的微囊藻彼此混杂。遗传距离分析结果显示，同一季节内微囊藻的遗传距离小于不同季节间的遗传距离（P〈0．01），太湖夏季水华主要由亲缘关系很近的微囊藻类群构成。

英文摘要：

In order to explore seasonal variation of Microcystis community in Taihu Lake, water samples were collected at four representative sampling sites （River Mouth, Meiliang Bay, lake-bay intersection, and Center of Taihu Lake） in four seasons. Two methods, microscopic evaluation and PCR denaturing gradient gel electrophoresis （DGGE） , were adopted to analyze the samples. The former did not find any significant seasonal variation of the dominant species （ Microcystis aeruginosa, Microcystis wesenbergii and Microcystis flos-aquae ） of the Microcystis community （ P 〉 0.05 ）. However, the latter discovered that the Microcystis communities in the samples collected in summer and winter were separated into two feature groups, but those in the samples collected in spring and autumn were intermingled. Moreover, analysis show genetic distance of Microcystis in the same season was smaller than those in different seasons （P 〈 0.01 ）. In Taihu Lake, estival blooms consist mainly of Microcystis groups that are closely related.