中文摘要：

将外来种沉水植物伊乐藻（Elodea nuttallii）、聚叶狐尾藻（Myriophyllum aquaticum）分别与其同科（或同属）的乡土种沉水植物轮叶黑藻（Hydrilla verticillata）、穗状狐尾藻（Myriophyllum spicatum）进行对比,分析了两种乡土沉水植物叶表面附植藻类的群落组成与结构特征,采用植物浸提液法研究不同浓度（0.5和2 mg·mL-1）的叶片浸提液对乡土种叶附植藻类生长和群落组成的影响。结果表明：两种外来沉水植物较乡土种具有更强的抑藻效应,且在高浓度下更显著;4种沉水植物浸提液均降低乡土种叶附植藻类的细胞总数,对群落物种丰富度和多样性的影响总体呈＂低浓度促进、高浓度抑制＂,且外来种的抑制更显著,其浸提液使得附植藻类群落组成结构趋于简单化;植物鲜样制备的浸提液较植物干样制备的浸提液具有更强的化感抑藻作用。

英文摘要：

A comparative study was made on the two exotic submerged macrophyte species （Elo- dea nuttallii and MyriophyIlum aquaticum） and their native congeners （Hydrilla verticillata and M. spicatum, with the differences in the community composition and structural characteristics of the epiphytic algae living on the two native species analyzed. Then, two concentrations （0.5 and 2 mg·mL-l ） of the leaf extracts from the exotic and native submerged macrophytes were used to explore how the extracts affect the growth and community composition of epiphytic algae living on the native macrophytes. The results showed that the extracts from the two exotic submerged mac- rophytes showed stronger algal inhibiting effect than those from the native ones, being more sig- nificant in high concentrations of the extracts. The extracts from the four submerged macrophytes all reduced the total number of the epiphytic algae living on the native macrophytes, and showed the trend that low concentration extracts could promote the species richness and diversity of the epiphytic algae, while high concentration extracts showed inhibiting effect. The extracts from ex- otic species had more significant negative effects, and made the epiphytic algae community com- position tend to be simple. The extracts from fresh plant materials showed stronger allelopathic algal inhibiting effect than those from dry ones.