Abstract: A comparative study was made on the two exotic submerged macrophyte species (Elodea nuttallii and Myriophyllum 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^-1) 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 macrophytes showed stronger algal inhibiting effect than those from the native ones, being more significant 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 exotic species had more significant negative effects, and made the epiphytic algae community composition tend to be simple. The extracts from fresh plant materials showed stronger allelopathic algal inhibiting effect than those from dry ones.

Key words: heavy material cadmium, transcriptome., soybean