Abstract: Based on the problem of cyanobacteria bloom, aloe-emodin was selected as an algaecide, and the effects on the growth, photosynthesis, enzyme activity and microcystins of Microcystis aeruginosa by aloe-emodin were studied. The results showed that aloe-emodin had a strong inhibitory effect on Microcystis aeruginosa. With the concentration increased, the inhibitory effect was significantly improved. When the concentration of aloe-emodin was 200 mg/L, after 12 days of contact, the inhibition rate of cyanobacteria reached to 90%; the inhibition rates of chlorophyll a and carotenoids in algae cells were 78% and 90%, respectively; the inhibition rates of phycocyanin, allophycocyanin and phycoerythrin in phycobiliproteins were 100%, 95% and 89%, respectively. The inhibition rates of soluble protein and algal toxin were 73% and 100%, respectively. During the experiment, the SOD and CAT activities of algae cells increased firstly and then decreased. Finally, the inhibition rates of SOD and CAT activities were 62% and 33%, correspondingly.

Key words: Microcystis aeruginosa, aloe-emodin, allelopathy, inhibition