南京8个湖泊超微真核浮游生物遗传多样性的研究

Genetic Diversity of Eukaryotic Picoplankton of Eight Lakes in Nanjing

用末端限制性片段长度多态性(terminal restriction fragment length poly morphism,T-RFLP)方法对南京市区8个不同营养水平湖泊的沿岸带和敞水带超微真核浮游生物(0.2～5.0μm)遗传多样性进行了研究,目的是了解不同营养水平湖泊超微真核浮游生物遗传多样性的差异以及影响这种差异的主要因子.T-RFLP结果表明,不同湖泊超微真核浮游生物的T-RFLP指纹图谱存在明显差异,沿岸带和敞水带末端限制性片段T-RFs平均值分别为16.4和15.9,其中营养水平中等的南湖沿岸带T-RFs最多(30个),营养水平较低的百家湖敞水带T-RFs最少(10个),除琵琶湖和莫愁湖外,沿岸带的超微真核浮游生物遗传多样性均比敞水带高.聚类分析表明,除百家湖、前湖、南湖外,其他湖泊沿岸带和敞水带的相似度都比较高.超微真核浮游生物遗传多样性与环境因子的典型对应分析(canonical correspondence analysis,CCA)表明,叶绿素a浓度与超微真核浮游生物群落结构和多样性显著相关(p=0.004).本研究表明,超微真核浮游生物遗传多样性受湖泊营养水平的影响,而且在敞水带和沿岸带存在差异.

The method of terminal restriction fragment length polymorphism （ T-RFLP） was used to study the genetic diversity of eukaryotic picoplankton （0. 2-5. 0 μm） in the pelagic and littoral zones in 8 lakes with different trophic status in Nanjing. The objectives of this study were to confirm the difference of the genetic diversity of eukaryotic picoplankton among lakes and the main factors affecting this difference. T-RFLP indicated that there were various fingerprints among lakes and zones. The average terminal restriction fragments （T-RFs） in the littoral and pelagic zones were 16. 4 and 15. 9,respectively. The littoral zone in Lake Nan and the pelagic zone in Lake Mochou had 30 T-RFs and 27 T-RFs,respectively. The T-RFs were the least abundant （10） in the pelagic zone in Lake Baijia with relatively low trophic status. The genetic diversity of eukaryotic picoplankton was higher in the littoral zone than that in the pelagic zone except Lake Pipa and Mochou. The cluster analysis indicated that the similarities of the littoral zones and the pelagic zones were very high except Lake Baijia,Qian and Nan. The canonical correspondence analysis between the genetic diversity of eukaryotic picoplankton and environmental factors revealed the concentration of chlorophyll a had the most important impact on the eukaryotic picoplankton communities （p = 0. 004）. The results indicated that the genetic diversity of eukaryotic picoplankton is affected by the trophic status and has the difference in the pelagic and littoral zones.