兽药土霉素对水稻幼苗根系及部分生理特性的影响

为了解抗生素对农作物生长的作用机理，选择中国养殖业中普遍使用的土霉素，采用水培试验研究了不同污染水平土霉素对苗期水稻根系生长、根系活力、叶片叶绿素含量和氧化酶活性等的影响。结果表明，土霉素污染对水稻地下部分的影响明显大于地上部分。低浓度（0.5和1 mg·L-1）的土霉素处理能促进水稻根系总长度和根表面积的增加，增强根系活力；但高浓度的土霉素（>5 mg·L-1）可显著降低水稻根系生物量，对根系活力、叶片叶绿素含量和氧化酶活性有明显的限制作用，增加根系相对质膜透性。研究认为，高浓度土霉素可对水稻幼苗产生毒害作用，限制水稻幼苗正常生长。

Effect of oxytetracycline on root growth and physiological characteristics of rice seedlings

In order to understand the influence of antibiotics on crop growth， oxytetracycline， which is widely used in livestock and poultry breeding in China， was selected to test the effects of different levels of antibiotics pollution on growth of rice seedlings， root activity， chlorophyll content and oxidase activity by hydroponic experiment. The results showed that the effects of soil oxytetracycline pollution on the underground part were greater than on the above-ground part of rice. Low oxytetracycline concentration （0.5 and 1 mg·L-1） increased root length and total root surface area， and enhanced root activity. But the high concentration of oxytetracycline （>5 mg·L-1） significantly reduced rice root biomass and chlorophyll content， restricted root activity and oxidase activity， and increased the relative membrane permeability of root. In conclusion， high concentrations of antibiotic could cause toxic effects on rice seedlings， which would limit the normal growth of rice seedlings.