“…It is all known that aquatic plants can release different types of allelochemical into the environment, and their contents and compositions are different for distinct aquatic plants (Tan et al, 2019). There is growing evidence that the combined effects of allelochemicals play an important role in the allelopathy of aquatic plants, and may help to reveal the mechanism of allelopathy in natural aquatic ecosystems (Gao et al, 2015(Gao et al, , 2017. A variety of Abbreviations: CFPs, chlorophyll fluorescence parameters; YII, the effective quantum yield of photochemical energy conversion in photosystem II (PSII); q P , a parameter estimating the fraction of PSII centers in open states based on a puddle model for the photosynthetic unit; q L , a parameter estimating the fraction of PSII centers in open states based on a lake model for the photosynthetic unit; q P(rel) , relative photochemical quenching; NPQ, light induced photoprotection through thermal dissipation of energy in the antenna system; q N , light induced photoprotection through thermal dissipation of energy in thylakoid membrane; q N(rel) , relative non-photochemical quenching; q CN , complete non-photochemical quenching; q TQ , total quenching; F v /F m , the maximum quantum yield of PSII photochemistry; F' v /F' m , the effective quantum yield of PSII photochemistry; UQF (rel) , relative unquenched fluorescence; EC 50 , the higher 50% effective concentrations; TI, toxicity index; TU, toxic unit.…”