Allelopathic Effects and Allelochemicals of Myriophyllum elatinoides on Microcystis aeruginosa and Selenastrum capricornutum

: The allelopathic effects of Myriophyllum elatinoides on algal growth were investigated and potential allelochemicals secreted by Myriophyllum elatinoides were analyzed. Myriophyllum elatinoides were co-cultivated with different initial concentrations (105, 106, 107, 108, and 109 ind.·L-1) of Microcystis aeruginosa and Selenastrum capricornutum. The optical density of each group was measured daily. The results showed that 2.5 g·(200 mL)-1 of Myriophyllum elatinoides has significant inhibition effect on Microcystis aeruginosa growth with initial concentrations of 107 ind.·L-1 and 108 ind.·L-1. However, there was no significant inhibition on the growth of Selenastrum capricornutum. Through solvent extraction and GC-MS analysis, hexadecanoic acid was extracted and determined as an allelochemical in Myriophyllum elatinoides. Additionally, three potentially novel allelochemical compounds secreted by Myriophyllum elatinoides were determined as follows:3-ethyl-3-methylheptane, triethyl phosphate and dibutyl phthalate.