[Allelopathy effects of ferulic acid and coumarin on Microcystis aeruginosa]

The inhibitory effects and allelopathy mechanism of ferulic acid and coumarin on Microcystis aeruginosa were investigated by measuring the D680 value, the content of chlorophyll-a, the electrical conductivity (EC) and superoxide anion radical O*- value. Ferulic acid and coumarin had allelopathic effects on the growth of M. aeruginosa and promoted the physiological metabolism at low concentrations while inhibited the metabolism at high concentrations. Obvious inhibitory effects were observed when the concentration of ferulic acid or coumarin was over 100 mg x L(-1). The average inhibitory rates reached 80.3% and 58.0% after six days when the concentration of ferulic acid or coumarin was 200 mg x L(-1). The content of chlorophyll-a was decreased while the EC value and O2*- concentration were promoted by higher concentrations of ferulic acid or coumarin, suggesting that the growth of algae was inhibited probably by the damage of cell membrane, increase in the content of O2*- and decrease in the content of chlorophyll-a. In addition, seed germination test elucidated that Ferulic acid was safer than Coumarin.