In this experiment, 0, 20, 40, 60, 80 and 100 mL/L of Microcystis aeruginosa(FACHB 930, 107 cells/mL) were cocultured with Spirodela punctata(ZH0051, 400 g/m2) in Hoagland which was diluted five times. Experimental results showed that the growth rate and the antioxidant enzyme activities (SOD, APX and CAT) of Spirodela punctata and the microcystins in the culture medium increased first and decreased with the increase of inoculation volume of Microcystis aeruginosa. In contrast, the content of microcystins inSpirodela punctata decreased first and then increased, and the accumulation of starch in the Spirodela punctata had showed a gradual decline. When the inoculation of Microcystis aeruginosa was 20 mL/L, the growth rate of Spirodela punctata reached its maximum value (3.64 g/m2·d). When the inoclum size was between 60~80 mL/L, the Spirodela punctata was able to remove nitrogen and phosphorus efficiently from the culture medium. It’s showed that when the concentration of Microcystis aeruginosa in water was about 2.0×108 cells/L (the inoculation level was 20 mL/L),Spirodela punctata can achieve a maximum biomass, relatively high starch accumulation rate, and high quality of nitrogen and phosphorus removal rate, and can effectively inhibit the growth of Microcystis aeruginosa.
