Inhibitory Effect of Hydrilla Verticillata on Planktonic Algae in Eutrophic Water

The experiment adopted the method of cultivating Hydrilla verticillata and algae in coexistence systems to study the inhibitory effect of Hydrilla verticillata on planktonic algae in eutrophic water. The results showed that allelopathic and competition of nutrition inhibitory effect were both affect the inhibition of Hydrilla verticillata on planktonic algae at initial concentration of 105 cells·mL-1, and the highest inhibition ratio on was 79% at undernutrition condition; opposite, allelopathic inhibitory effect played a major role at nutritional sufficiency, the highest inhibition ratio was 39%. Hydrilla verticillata played a role of “promoting with low biomass while inhibiting with high biomass” on planktonic algae, the optimal biological dosage of Hydrilla verticillata on inhibiting planktonic algae at initial concentration of 105 cells·mL-1 was 12g·L-1. Hydrilla verticillata allproduced inhibitory effect on planktonic algae at different initial concentrations, and the greater the initial concentration of planktonic algae, the higher the inhibition ratio of Hydrilla verticillata on planktonic algae.