长江中下游优势沉水植物遗传多样性的地理格局研究

Lakes in the mid-lower reaches of the Changjiang (Yangtze) River are connected with each other through the river system. Man's activities have become the most important factor to affect the distributions of macrophytes. In this study, we use random amplified polymorphic DNA (RAPD) markers to evaluate the patterns of the genetic diversities of the dominant submersed macrophytes in the area. Potamogeton maackianus and Myriophyllum spicatum showed relatively higher genetic variations with Shannon indexes 0.4139 and 0.3849 respectively. AMOVA analyses found 63.78% of the total genetic variation of P. maackianus existed among populations and 36.22% within them, while M. spicatum had only 39.32% of total genetic diversity among populations and 60.68% within them. Different P. maackianus populations had very limited gene flow. Genetic similarities between different P. maackianus populations had no obvious relationships with the geographic and historical relations of the lakes where they occurred. However, lakes had lower influence on the genetic exchanges between different M. spicatim populations. In general, M. spicatum populations from lakes with shorter distances had relatively higher genetic similarities. The different patterns of genetic diversities of the two macrophytes were considered closely related with their different clonal propagation and dispersal ways. Genetic diversities of macrophytes in habitats connecting with each other need further studies to understand more about the population dynamics and genetic differentiations.

选择长江中下游地区若干优势沉水植物，运用分子生物学技术对其居群遗传多样性的地理分布格局进行研究，以阐明水生植物的遗传多样性中心问题；结合对湖泊水生植被演替及植物繁殖散布模式的分析，探讨水域环境的空间分割和繁殖散布模式对水生植物居群遗传多样性的影响，研究水生植物居群之间的相互关系。