Abstract: The allelopathic effects of Salix babylonica leaf extracts on the growth and morphology of Chlorella pyrenoidosa were investigated by measuring the cell density of treated algae. It was shown that the leaf extracts of S. babylonica had definite allelopathic effects on C. pyrenoidosa, depending on their concentration. The EC50, 96 h value of the extracts was 1182 g·L-1. Lower concentrations (10 and 20 g·L-1) of the extracts inhibited the algal growth first and promoted it then, while higher concentration (30 g·L-1) of the extracts showed inhibitory effect all the time. The maximum inhibitory rate of the extracts at concentrations of 10, 20, and 30 g·L-1 was 375%, 393%, and 565%, respectively. After treated with the extracts, part of C. pyrenoidosa cells aggregated, expanded, turned transparent, and finally lysed. The amount of the aggregated cells increased with increasing concentration of the extracts. When treated with 30 g·L-1 of the extracts, C. pyrenoidosa cells largely aggregated, and precipitated as cell pellets to the bottom of the container.

Key words: Acetochlor, Methamidophos, Fungi community, PCR-DGGE, Black soil