洞庭湖浮游生物群落DNA指纹拓扑结构与物种组成对应关系

Corresponding relations between DNA fingerprinting topological structure and species composition of plankton community in Dongting Lake

对东洞庭湖7个采样站点的浮游生物群落进行了DNA多态性的RAPD指纹分析和物种组成的分类鉴定,并通过聚类分析探讨了DNA指纹拓扑结构与物种组成对应关系.结果如下:(D筛选出的11条随机引物共获得148条长度在180～2000bp的谱带,多态率为98.6%,各引物扩增谱带数在11～16不等;各站点平均有57.6条谱带,其中Ⅵ站最多(70条),Ⅳ站最少(45条),而Ⅰ站的特有带最多(7条),Ⅱ站最少(2条);(2)共观察到54种/类浮游生物,其中Ⅳ站出现的最多(27),其它各站点在7～13不等,分布概率在85%以上的只有直链硅藻(Melosira sp.).相似性聚类分析表明:7个站点的浮游生物群落可以划分为两大类--Ⅳ站作为单独的一类而明显有别于其它6站;并且,RAPD分析在此基础上将Ⅱ、Ⅲ、Ⅴ站和Ⅰ、Ⅵ、Ⅶ站进一步分作两小类.因此,研究说明浮游生物群落DNA指纹拓扑结构与物种组成是密切相关的,这类资料的积累将会为生态系统功能、机理的解释或阐明提供一些启示.

As the confluence of natural resources, biodiversity has become the focus of ecological study. Plankton, as an Important its high s variables part of the biodiversity and cosmopolitan organisms, plays a key rloe in nutrient cycling and energy flows. Because of its high sensitivity to environmental changes and its short life span, plankton is also used as indicators of environmental variables and aquatic ecosystem healty. However, most of the studies have focused on investigating the community composition. To completely reveal the molecular mechanism of some ecological functions, the authors extended the DNA fingerprinting techniques to plankton community and obtained some valuable information. The present study was designed to further explore the genetic diversity of plankton communities in Dongting Lake and to examine the relationships between DNA polymorphism and species composition. Environmental samples were obtained from seven sampling sites in Eastern Dongting Lake. Following the species identification, the DNA polymorphism was assessed by random amplified polymorphic DNA （RAPD）, their relations were then assessed with cluster analysis. The results were： （i） 11 of 80 screened random primers used in the study amplified a total of 148 observable bands, 98.6% of which were polymorphic and the number of bands scored per primer varied from 11 to 16; the mean number of amplified bands at different stations was 57.6, samples from station Ⅵ had the maximum number （70） and the station Ⅳ the minimum （45）; the number of individual bands at station Ⅰ was the most and the station Ⅱ was the least; （ii） a total of 54 planktonic taxa were identified, most of them to species level or higher; the detected taxa at the station Ⅳ were the most （27） and ranged between 7 and 13 at other stations, some species were detected at several stations, but much more taxa were restricted to single stations. Cluster analysis based on RAPD markers and species composition showed that the target communities could be grouped into two clusters. The station Ⅳ comprised a single cluster, and another cluster contained the other six stations. Additionally, the clustering of RAPD makers could set further divide the stations Ⅱ,Ⅲ,Ⅴ and Ⅰ,Ⅵ,Ⅶ to two subgroups. In conclusion, our results suggested that the DNA polymorphism of plankton community was closely related to the species composition, and the genetic data accumulated will provide inspiration for elucidating the ecological function and mechanism.