Differential responses of epiphytic and planktonic toxic cyanobacteria to allelopathic substances of the submerged macrophyte stratiotes aloides

摘要

The present study investigates the allelopathic effects of Stratiotes aloides on the growth and antioxidative biomarkers of epiphytic and planktonic toxic cyanobacteria in a batch experiment over a 15-day exposure to different concentrations of aqueous acetone extract of this macrophyte. The results showed that epiphytic and planktonic species of cyanobacteria showed differential responses to the allelopathic activity of this macrophyte. S. aloides extract reduced the growth, alkaline phosphatase activity (APA) and toxin production of the planktonic cyanobacterium, Anabaena variabilis, with an increase in lipid peroxidation, glutathione and activities of antioxidative enzymes of this cyanobacterium. Conversely, this extract did not affect the growth and increased the toxin production in epiphytic cyanobacteria, with no significant effect on lipid peroixdation or the activities of APA and antioxidative enzymes of these species. This study is the first to suggest that the macrophyte S. aloides supports the growth and toxin production of its epiphytic cyanobacteria.