兽药污染土壤对小麦和白菜根伸长抑制的毒性效应

含有残留兽药的粪便作为有机肥施入农田，可造成农业土壤污染，对人类健康和生态系统产生潜在危害。为评价兽药污染的潜在生态影响，本试验采用室内生长箱培养的方法，测定了黄潮土在2种常用兽药土霉素、伊维菌素污染条件下，对2种作物（小麦和白菜）根伸长、芽伸长的抑制率，以及复合污染毒性效应。结果表明，土壤中土霉素、伊维菌素浓度与作物根伸长及芽伸长抑制率呈显著线性相关（P〈0．01）。2种兽药对植物根、芽伸长抑制强度为：伊维菌素〉〉土霉素；在药物的胁迫下，作物的根伸长较芽伸长敏感，2种作物的敏感性为：小麦〉白菜，小麦为兽药污染的敏感植物。土霉素和伊维菌素的复合污染产生明显的协同作用。

Toxicological Effects of Veterinary Drugs in Soil on the Inhibition of Root Elongation of Wheat and Chinese Cabbages

The animal excrements containing veterinary drugs manured into field soils would result in agricultural soil pollution, and which drew an important potential threat on the human health and ecosystem. To evaluate the potential toxicological effects of veterinary drugs, the inhibition rates of two kinds of veterinary drugs （oxytetracycline, ivermectin） on two crops （wheat and Chinese cabbages） were determined in the yellow moist soil by indoor cultivating, and the toxic effect of combined pollution was investigated. Results indicated that there was a significant linear relationship between the concentration of oxytetracycline and ivermectin and the inhibition rates of crops（P〈0.01 ）. The inhibition of those two veterinary drugs on plant elongation was ivermectin〉〉oxytetracycline. Under the stress of the drugs, root elongation of crops was more sensitive than shoot elongation, the sensitivity of wheat was larger than that of Chinese cabbages. According to ICe,（half inhibition concentration）, for oxytetracycline, the order of sensitivity was wheat root elongation〉 Chinese cabbages root elongation〉 wheat shoot elongation〉Chinese cabbages shoot elongation; For ivermectin, the order was wheat root elongation〉wheat shoot elongation〉 Chinese cabbages root elongation〉Chinese cabbages shoot elongation. The results indicated that root elongation of the wheat was the most sensitive under the stress of the veterinary drugs. When oxytetracycline and ivermectin were combined, a markedly synergistic effect was observed.