Abstract:In order to explore the effects of veterinary tetracycline on physiological characteristics of maize seedlings, pot experiment was conducted to study the effects of different substrates (single application of worm cast, fungal chaff, microbial inoculum, biochar and its combined application with microbial inoculum) on growth of maize seedlings under the stress of exogenous tetracycline pollution. The results showed that tetracycline inhibited significantly the maize biomass, and its inhibitory effect on root length was significantly greater than that on plant height. The inhibitory effect of tetracycline on maize plant height and root length could be alleviated by adding different substrates, and the effect of JK (fungal chaff) and JJ (fungal chaff + microbial inoculum) treatment was the most significant, with the increase of 17.29% and 30.08%, respectively. Tetracycline significantly increased SOD activity in maize by 3.34%, and inhibited CAT and POD activity by 10.98% and 46.68%, respectively. Among the treatments with different substrates, QY (worm cast) treatment had the most significant effect on promoting antioxidant enzyme system balance. Tetracycline could increase the content of proline, malondialdehyde, soluble sugar, soluble protein and total flavonoids in maize, among the treatments with different substrates, JK, JJ, QY, S and JK treatments had the most significant reduction effects, the decline rates were 29.09%, 50.88%, 42.01%, 50.23% and 35.79%, respectively. Correlation analysis showed that proline and malondialdehyde both were extremely significantly positively correlated with soluble protein and total flavonoids, POD activity had the strongest correlation with soluble sugar, malondialdehyde had the strongest correlation with total flavonoids. In conclusion, adding different substrates could effectively alleviate the toxic effect of tetracycline on maize seedlings. The general trend showed that JK, JJ and QY had the best effect. Through this study, we could select the best substrates and application methods which could effectively reduce the effects of tetracycline on plant growth, provide reference for the research of physiological toxicity of tetracycline to plants, and also provide scientific basis for the risk assessment of antibiotic on plants.