Oxytetracycline （OTC） is one of broad-spectrum antibiotics, which may enter the environment through various pathways and cause potential ecotoxicological effects. Experiments were conducted in hydroponic system to investigate the uptake of OTC and its phytotoxicity to lettuce. The effeets of OTC （1 - 10 mg·L^-1） on lettuce were evaluated after cultivating for 18 days. It was found that the OTC uptake by lettuee increased with the initial OTC concentrations increasing. The growth of lettuce root was inhibited at the OTC eoneentration of 1mg·L^-1, but the foliage was not affeeted. Under the eoncentrations of OTC more than 5 mg· L^-1, both root and foliage exhibited phytotoxieity response, and the root was more sensitive to OTC than foliage. Furthermore, with the increase of initial OTC concentration, the water absorption capacity tended to decrease, and the uptake of trace elements （Fe, Cu, Zn and Mn）by lettuce were inhibited as well, whieh may be due to the complexation of OTC with metals. In the four traee elements, the inhibition effect of Mn by OTC was more remarkable than the other three metals, and the inhibition of Zn was the least, pH could affect the uptake of OTC （ 1 mg·L^-1OTC, pH 5-8）, but the influence of pH on the growth of lettuee was not significant. The results are helpful to assess the uptake and phytotoxicity of OTC to plants.
Journal of Agro-Environment Science( J. Agro-Environ. Sci.)