[Effects of exogenous tetracycline on rape soil enzyme activity and rape quality]

This paper studied the effects of applying different concentration (0, 0.30, 0.60, and 0.90 mg x kg(-1)) tetracycline on the soil enzyme activities and rape quality. The results showed that soil urease activity after applied 0.30, 0.60, and 0.90 mg x kg(-1) of tetracycline and soil suerase activity after applied 0.90 mg x kg(-1) of tetracycline were inhibited in the whole cultivating period, while the soil sucrase activity after applied 0.30 and 0.60 mg x kg(-1) of tetracycline showed a trend of activation-inhibition-activation. Soil proteinase activity showed a trend of inhibition-activation, and the extent and duration of the inhibition and activation had significant positive correlations with tetracycline concentration (r = 0.950 * *). Soil catalase activity showed activation first and turned to irregular then. The action duration of tetracycline on the activities of soil urease, catalase, sucrase and proteinase were 7 weeks, 6-8 weeks, 7 weeks, and 6-7 weeks, respectively. At harvest time, the soluble sugar contents in rape leaves after applying 0.30, 0.60, and 0.90 mg x kg(-1) of tetracycline decreased dramatically by 91.99%, 87.92%, 90.12%, while the soluble protein content increased by 26.47%, 28.13%, and 23.22%, respectively, compared to the control.