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The submerged plant allelopathic effects on the growth of a harmful bloom-forming cyanobacterium (Microcystis aeruginosa): a diversity gradient experiment

Xia Gao, An-Guo Gao, Zhong-Xi Bai, Jin-Rui Yuan, Jian Liang, Ai-Ping Wu

Abstract

Context: Although it is well known that aquatic plants have allelopathic effects on phytoplankton, the allelopathic effects of different diversity of aquatic plants on phytoplankton are not well known. Using diverse mixed submerged plant allelopathy to control cyanobacteria maybe a potential strategy for eutrophic aquatic ecosystems. Aims: To determine the allelopathic effects of submerged plants with different diversity on cyanobacteria. Methods: We determined the allelopathic effects of four submerged macrophytes along a diversity gradient on the growth of a bloom-forming alga, Microcystis aeruginosa. Key results: The results showed that the alga density, alga growth rate and Chl-a concentration were negatively impacted by plant exudates. Moreover, the alga growth inhibition increased with submerged plant diversity. Additionally, the alga growth inhibition caused by Ceratophyllum demersum was the most significant among the four species. Conclusions: These results indicated that submerged plants had obvious allelopathic effects on the growth of M. aeruginosa, and the allelopathic effects increased with species diversity. Implication: Accordingly, using diverse mixed submerged plant allelopathy to control cyanobacteria is an alternative potential strategy in eutrophic aquatic ecosystems. However, the effects of submerged plant allelopathy on other aquatic organisms and water quality need to be further studied to ensure its safety

MF23149  Accepted 11 June 2025

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