关键词: 化感作用;富营养化;沉水植物;铜绿微囊藻

Abstract:

Allelopathy is an important trait in competition between macrophytes and phytoplankton in freshwater ecosystems. Allelopathic effects of submerged macrophytes such as P. crispus, P. lucens, and C. demersum on Microcystis aeruginosa were assessed using co-culture experiments under controlled laboratory conditions. Excluding the influence of nutrient and light intensity condition, the results showed that all three macrophytes had significant allelopathic effects on the growth of M. aeruginosa, and the effects depended on initial algae cell density, the species and biomass of the macrophyte. The growth of M. aeruginosa was significantly inhibited by 10g／L and 5g／L of P. crispus at low initial cell density. At high initial cell density 10g／L P. crispus showed a more inhibitory effect on M. aeruginosa than 5g／L P. crispus. The allelopathic effects of 7g／L and 4g／L P. lucens on M. aeruginosa at two initial cell densities were very significant. Both 7g／L and 4g／L C. demersum had significant growth inhibition on M.aeruginosa at low initial cell density, while less effects were observed at high initial cell density. The allelopathic effects of the three submerged macrophytes increased as P. lucens>P. crispus>C. demersum. In an experiment of the three submerged macrophytes culture filtrates, culture water showed stimulatory growth effects on M. aeruginosa.

Key words:  allelopathy; eutrophication; submerged macrophytes; Microcystis aeruginosa