Ecological Toxicity Effects of Artemisinin Algicidal (AMA) on Submerged Plant Vallisneria natans

Artemisinin algaecide (AMA) had a significant inhibitory effect on algae in our previous study, but the impact on coexisting submerged plants was unclear. In this study, we investigated the impacts of AMA with varying concentrations (1‰, 5‰ and 10‰) on the growth, antioxidant response and microbial community of Vallisneria natans (V. natans). The results revealed a significant reduction in biomass in V. natans upon exposure to AMA, indicating an inhibitory of V. natans. Furthermore, malondialdehyde (MDA) content increased significantly in three treatment groups, and catalase (CAT) increased significantly in the 10‰ treatment group, while superoxide dismutase (SOD) had little change in all groups, indicating complex antioxidant responses to AMA. Notably, the High-throughput sequencing results showed that AMA significantly altered microbial abundance and community structure of V. natans. Alpha diversity results indicated that AMA increased the diversity of the microbial community in V. natans, but it had little impact on the dominant bacterial phylum. These results provide necessary information to assess the potential ecotoxicity of AMA to submerged plants during algal suppression and draw more attention to their use in natural water bodies.