Allelopathic Effect on Microcystis aeruginosa and Synedra acusvar by Different Organs' Extract of A. Macrorrhiza

In order to study the allelopathic effect on M. aeruginosa and S. acusvar by different concentrations of A. macrorrhiza organs' extract, chlorophyll, a content of algae, was investigated by the root, stem, leaf of A. macrorrhiza. The results show that: root extract on experimental algae showed inhibitory effect of low concentration, high concentration of promotion, and leaf extract on experimental algae showed allelopathic inhibition. Leaf extract of allelopathic inhibitory ability is higher than root extract. The allelopathic inhibition enhanced gradually with increase of concentration. The inhibition rates were 93% and 58% on M. aeruginosa or S. acusvar when the concentration of leaf extract was 10 g/L on 18th day. A. macrorrhiza stem extract promoted the growth of experimental algae, and M. aeruginosa's effect of promotion is stronger than on S. acusvar.