四环素类抗生素对不同蔬菜生长的影响及其富集转运特征

本研究探讨了四环素类抗生素(TCs)对两种蔬菜生长的影响及其在蔬菜体内的富集和转运特征,以期为四环素类抗生素的植物毒性和对人体健康的风险评价提供理论基础.采用土培试验研究了不同水平(0、50和150 mg·kg-1)的四环素类抗生素(四环素TC、土霉素OTC、金霉素CTC)对生菜和小白菜生长、抗生素含量及其富集转运特征的影响.结果表明,TCs总体上抑制了生菜的生长,地上部和地下部鲜重分别较CK降低了1.56%~26.84%和17.36%~51.04%,小白菜地上部和地下部鲜重反而较对照提高了3.7%~7.3%和3.1%~82.2%.TCs在一定程度上增加了生菜和小白菜的气孔导度(Gs)和蒸腾速率(Tr),抑制了生菜的净光合速率(Pn),Pn在TCs为150 mg·kg-1时较CK降低了32.43%~82.43%.TCs还抑制了生菜和小白菜的SOD活性,较CK降低了29.17%~223.12%,以OTC的抑制作用最强.生菜和小白菜的MDA含量在TCs为150mg·kg-1时达到最大值(生菜地上部除外).小白菜地上部和地下部TCs的含量均高于生菜,以CTC处理的小白菜和生菜TCs含量较高.种植生菜的土壤TCs残留量高于小白菜土壤,以OTC处理的土壤TCs残留量最高.小白菜对TCs的富集系数和转运系数分别是生菜的1.07~7.35倍和1.15~2.25倍.3种四环素类抗生素中以OTC和CTC的生态风险较大.

Effects of Tetracycline Antibiotics on Growth and Characteristics of Enrichment and Transformation in Two Vegetables

Pot experiments were carried out to study different levels (0, 50, and 150 mg·kg^-1) of three tetracycline antibioticstetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC)] on the growth, concentration of tetracycline antibiotics, and their characteristics of enrichment and transformation in two kinds of vegetables (lettuce and Chinese cabbage). The results showed that the fresh weight of shoots and roots of lettuce decreased by 1.56%-26.84% and 17.36%-51.04%, respectively, when exposed to tetracycline antibiotics compared to the control, while the fresh weight of shoots and roots of Chinese cabbage increased by 3.7%-7.3% and 3.1%-82.2%, respectively. The stomatal conductance (G_s) and transpiration rate (T_r) of lettuce and cabbage increased when exposed to tetracycline antibiotics, while the net photosynthetic rate (P_n) of lettuce decreased by 32.43%-82.43% at 150 mg·kg^-1 of TC compared to the control. Compared to the control, the activities of SOD in lettuce and cabbage decreased 29.17%-223.12% when exposed to tetracycline antibiotics, and the lowest activities of SOD in lettuce and cabbage were found in OTC treatments. The highest content of MDA in lettuce and cabbage was observed at 150 mg·kg^-1 of TC (except for lettuce leaves). The contents of tetracycline antibiotics in the shoots and underground portions of Chinese cabbage were higher than that of lettuce, and higher contents of tetracycline antibiotics in vegetables were found with the CTC treatments. The residual amount of antibiotics in lettuce soil was higher than that in the Chinese cabbage soil, and the highest residual amount in the soil was observed with the OTC treatment. The bioconcentration factors (BCF) and transport factor (TF) of Chinese cabbage were, respectively, 1.07-7.35 and 1.15-2.25 times that of lettuce. OTC and CTC were more easily concentrated in the two vegetables. Therefore, OTC and CTC may bring a higher ecological risk.