Toxicity of chlortetracycline and oxytetracycline on Vallisneria natans (Lour.) Hare

Tetracyclines are frequently detected in water bodies due to their widespread use aquaculture and animal husbandry. A hydroponic experiment was conducted explore the phytotoxic effects of Vallisneria natans (Lour.) Hare exposed various concentrations chlortetracycline (CTC) oxytetracycline (OTC) (0, 0.1, 1, 10, 30, 50, 100 mg/L) for 7 days (7 D) 14 (14 D), respectively. The results showed that similar OTC treatment D, relative growth rates (RGR) catalase (CAT) activity V. natans, after D CTC exposure, decreased significantly at 10 mg/L 30 mg/L, content soluble protein notably when ? mg/L. hydrogen peroxide (H2O2) stimulated while it hardly changed CTC. After malondialdehyde (MDA) H2O2 contents were higher than those control group under a high concentration (? mg/L), but they did not change polyphenol oxidase (PPO), first significant increase then decreases; maximum value (125% control) noticed CTC, remained unchanged OTC. 0.1 OTC, RGR, CAT, peroxidase (POD) activities, evidently harm chlorophyll reductions carotenoid more pronounced b. suggest both have negative effect on can cause oxidative damage harms metabolism process without inducing damage. Overall, toxicity is stronger