[Ecotoxicological effects of tetracycline on the seedling development of Chinese white cabbage (Brassica rapa L. chinensis group.) in soil].

The ecotoxicological effects of tetracycline (TC) on the early growth and seedlings development of Chinese white cabbage were investigated using the pot-culture method. The results showed that the stem elongation of the cabbages was promoted, while the root elongation and fresh weight of the cabbages were inhibited by 1-100 mg/kg TC. After a 28-day exposure, the inhibition rate of root elongation was up to 36.0% and that of fresh weight was up to 34.6% stressed by 100 mg/kg TC. With the exposure time of TC prolonged, the content of chlorophyll in leaves of the cabbage seedlings stressed by 100 mg/kg TC was significantly lower than that treated by other concentrations of TC, with the inhibition rate of chlorophyll was 21.7% - 29.0%. After a 7-day exposure to TC, the content of soluble protein (SP) and malondialdehyde (MDA) in the cabbage seedlings changed insignificantly. With the exposure time of TC prolonged, the content of SP in the cabbage seedlings decreased significantly, while the content of MDA increased significantly. Moreover, the activity of SOD, POD and CAT in Chinese white cabbage seedlings was inhibited by 1-100 mg/kg TC. The inhibition rates of SOD, POD and CAT activity exposed to 100 mg/kg TC were 33.9% - 45.3%, 33.8% - 67.7% and 29.6% - 57.7%, respectively. It suggested that TC has ecotoxicological effects on Chinese white cabbage seedlings with a chronic exposure.