Abstract: Chinese cabbage (Brassica chinensis L.) was selected to investigate the toxic effects of six antibiotics (tetracycline, oxytetracycline, chlorotetracycline, doxycycline, chloromycetin and sulfadimidine) on the seed germination, root (shoot) elongation, soluble proteins and antioxidant enzymes of the Chinese cabbage. The results showed that 0.5-5 mg·L^-1 antibiotics did not inhibit the germination rate, while the seed germination was significantly inhibited with the increasing of antibiotics concentration. There was a good doseeffect relationship between the antibiotic concentration and the inhibition rate of root (shoot) elongation. According to the EC₅₀ values of root inhibition of the Chinese cabbage stressed by the antibiotics, the toxicity of the antibiotics was in order of sulfadimidine > chloramphenicol > chlortetracycline > tetracycline > doxycycline > xytetracycline. The contents of soluble proteins of Chinese cabbage induced by the antibiotics were significantly different among the groups. Moreover, the balance of the antioxidant enzyme system of Chinese cabbage seedlings was destroyed by the tested antibiotics.

Key words: oxidation resistance, Kobresia pygmaea, K. tibetica, warming, morphology