根表铁膜对凤眼莲吸收环丙沙星的影响

Effect of Root Surface Iron Membrane on Absorption of Ciprofloxacin by Eichhornia crassipes

为探讨铁离子不同浓度处理下水生植物根表铁膜形成及其对环丙沙星(ciprofloxacin,CIP)吸收的影响,采用室内模拟试验,分析0.1 mg·L^(-1)CIP胁迫下不同浓度铁离子(0、10、20、50、100和150 mg·L^(-1))对凤眼莲根系生理生化及CIP富集量的影响。结果表明,不同浓度铁离子对凤眼莲根系孔隙度和泌氧量无显著影响,而根系活力随着铁离子浓度增加呈上升趋势;铁离子促进凤眼莲根表铁膜形成,150 mg·L^(-1)铁离子处理下凤眼莲根表铁膜量最大,且根表吸附CIP含量最多,而根系中吸收CIP含量显著降低。铁离子对凤眼莲根系生理生化无显著影响,而有利于凤眼莲根表铁膜量增加,促进根系表面CIP的吸附作用,阻碍根系对CIP的吸收作用,降低CIP对植物造成的伤害。

The formation of iron membrane on the root surface of aquatic plants and its effect on the absorption of ciprofloxacin(CIP)are two critical issues for phytoremediation of antibiotic pollution.To address these two issues,this study presented experimental results under different concentrations of iron ions(0,10,20,50,100,and 150 mol·L^(-1))under the stress of 0.1 mg·L^(-1)CIP.The effects of different concentrations of iron ions on the physiological and biochemical characteristics of roots and the concentration of CIP in roots were studied.Tests showed that:(1)Different concentrations of iron had no significant effect on the porosity and oxygen production of roots,but the root activity increased with the increase of iron concentration.(2)Iron ions promoted the formation of iron membrane on root surface of lotus.The amount of iron membrane on root surface of Eichhornia crassipes and the absorbed CIP content on root surface both reached the peak at the iron ion concentration of 150 mg·L^(-1).(3)The accumulated CIP content in root decreased significantly with the increase of iron ions.(4)Iron ion had no significant effect on the physiological and biochemical characteristics of the root,whereas it was beneficial to increase the amount of iron membrane on the root surface,promote the adsorption of CIP on the root surface,hinder the uptake of CIP in root,and reduce the damage caused by CIP to the plant.