Abstract: By the methods of single factor toxicity test and histological observation, this paper studied the acute toxicity of bisphenol A (BPA) and p-nitrophenol (p-NP) to Misgurnus anguillicadatus and the histological changes of M. anguillicadatus gill. The median lethal concentration (LC₅₀) and safe concentration (SC) were calculated. The LC₅₀ of BPA for 24, 48, 72, and 96 hours were 8.32, 8.02, 6.97 and 6.43 mg·L^-1, respectively, and the SC was 2.24 mg·L^-1; while the mean LC₅₀ values of p-NP for 24, 48, 72, and 96 hours were 19.14, 17.58, 16.98, and 14.69 mg·L^-1, respectively, and the SC was 4.40 mg·L^-1. After exposed to BPA and p-NP, the cells of branchial leaflets fell off, and the branchial leaflets became thin. Both BPA and p-NP had high toxicity to M. anguillicadatus, and BPA had higher toxicity than p-NP. With the increasing concentration and exposure time of BPA and p-NP, their toxicity effects to M. anguillicadatus increased, and the damage on gill of  M. anguillicadatus was more severe.

Key words: Lysimachia congestiflora, Light intensity, Clonal architecture, Ramet population characteristics