武汉东湖浮游生物群落DNA多态性与富营养化

The DNA polymorphism of plankton community and eutrophication in Lake Donghu, Wuhan

对武汉东湖不同程度富营养化湖区 ,即站 、站 与站 浮游生物进行了群落级 DNA多态性的 DNA指纹研究 ,并就其拓扑结构与富营养化特征参数之间关系进行了分析。实验结果如下 :(1)各站点总氮、总磷及叶绿素 a分别为 1.14 6～ 2 .2 35mg/ L、0 .0 13～ 0 .2 10 mg/ L 和 4 0 .2 5～ 10 9.2 2 μg/ L;(2 )所筛选的 5个随机引物共获得 2 9个扩增位点 ,其中多态位点占75 .9% ,各引物扩增谱带数在 2～ 6间。站 的扩增条带数最多、谱带多态率最高 (6 9.6 % )、特有带最多 ;(3)特定浮游生物类群的特异性 PCR扩增谱带为 1～ 6条不等 ,站间差别甚小。聚类及综合分析表明 :DNA指纹拓扑结构与浮游生物及特定浮游生物类群的物种多样性丰度相吻合 ,并与富营养化主要指示参数存在明显相关 ,即在一定范围内浮游生物群落 DNA多态性与富营养化程度呈反方向发展 ,而原生动物则表现出同向性发展趋势。因此 ,群落级 DNA指纹分析不仅能为生态学研究洞开一片新颖的视窗 。

With increasing water pollution, much more attention has been paid to biodiversity and its relationship with environment in order to preserve biodiversity and manage water resources scientifically as well. Based on the previous investigation of the authors, which demonstrated that it is feasible to show genetic diversity by DNA fingerprinting, this study is further going to explore the relationship between DNA polymorphism of plankton community and eutrophication of target lake. To assess the DNA polymorphism of plankton community, environmental samples were obtained from Donghu Lake areas with different trophic levels. After measuring the concentrations of TN, TP and Chl-a, the DNA polymorphism was assessed by random amplified polymorphic DNA (RAPD) and PCR amplification with specific primers. Furthermore, correspondences between topology structure of DNA fingerprinting and three crucial factors (TN, TP, Chl-a) of eutrophication was analyzed. The experimental results were: (i) the concentrations of TN, TP and Chl-a at different sampling stations were 1.146～2.235 mg/L, 0.013～0.210 mg/L and 40.25～109.22μg/L, respectively; (ii) five of twenty screened random primers used in the survey generated a total of 29 scorable RAPD bands, 75.9% of which were polymorphic and the number of bands scored per primer varied from two to six, additionally, the frequencies of polymorphisms at station Ⅲ was the highest (69.6%), both the individual fragments and total number of bands at station Ⅲ were the most; and (iii) the PCR amplification targeted as the peculiar group of plankton (protozoan community) showed that the number of bands scored per primer varied from one to six, and the marked discrepancy between stations was unobvious. Based on these experimental results, the clustering and synthetically analysis showed that the topology structure of DNA fingerprinting was correspondent to the species diversity of plankton community, so was the protozoan data and the eutrophication data. Concretely speaking, in a certain range, the DNA polymorphism of plankton community goes conversely to the level of eutriphication, while the protozoan community goes on the same direction.In conclusion, results of the present investigation have indicated highly that DNA fingerprinting on plankton community would provide a new idea for ecological study, and it will be possible to conceive one simple and efficient forecasting system for the crisis of water resource.