Inhibitory effect and mechanism of three macrophytes extract on Microcystis aeruginosa growth and physiology

Abstract

Macrophytes are a promising source of bioactive compounds with potential applications in the biocontrol of harmful cyanobacteria blooms. In this study, we investigated the inhibitory effects of extracts from three macrophytes (Nasturtium officinale, Potamogeton natans and Ranunculus aquatilis) on Microcystis aeruginosa. We assessed physiological indicators of inhibition on M. aeruginosa, including lipid peroxidation, protein content, superoxide dismutase activity, catalase activity and growth. The chemical composition of the macrophyte extracts and their specific allelochemicals were analysed using high-performance liquid chromatography (HPLC). Results showed that M. aeruginosa growth was significantly inhibited after 8 days of exposure, with inhibitory rate varying from 96.98% to 99.01%. The macrophyte extracts caused cyanobacterial cell membrane and antioxidant defence system damage. Thirteen different compounds were identified as allelochemical compounds that could be responsible for M. aeruginosa growth inhibition and oxidative stress. Our findings suggest that allelopathic compounds from macrophytes may be used to effectively control cyanobacteria blooms and promote the restoration of aquatic ecosystems.