Toxicological effects involved in risk assessment of rare earth lanthanum on roots of Vicia faba L.seedlings  

作　　者：Chengrun Wang Mei He Wen Shi Jessie Wong Tao Cheng Xiaorong Wang Lingling Hu Fenfen Chen 

机构地区：[1]School of Life Science, Huainan Normal University, Huainan 232001, China [2]State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China [3]Department of Chemical and Biochemical Engineering, University of Western Ontario, London, ON, N6A5B9, Canada [4]Department of Biology, University of Western Ontario, London, ON, N6A5B9, Canada

出　　处：《Journal of Environmental Sciences》2011年第10期1721-1728,共8页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 20877032);the Foundation of State Key Laboratory of Pollution Control and Resources Reuse of China (No. PCRRF08011)

摘　　要：Combined chemical analyses and biological measurements were utilized to investigate potential toxicological effects and possible mechanisms involved in risk assessment of rare earth elements （REEs） on Viciafaba L. seedlings, which were hydroponically cultivated and exposed to various concentrations of lanthanum （La） for 15 days. The results showed that La contents in both the solution and roots increased with the increase of extraneous La, contributing to hormetic dose responses of superoxide dismutase （SOD）, catalase （CAT）, guaiacol peroxidase （GPX）, ascorbate peroxidase （APX） and endoprotease （EP） isozymes activities, and HSP 70 production enhanced at low doses but suppressed at higher doses of La. These physiological responses constituted antioxidant and detoxification systems against La-induced oxidative stress. The elevated La levels also contributed to oxidatively modified proteins, which were most responsible for subsequent cell death and growth retardation of the roots. By combination of hormetic and traditional threshold dose levels, the threshold dose range was deduced to be 108-195 μg La/g dry weight in the roots, corresponding to 0.90-3.12 mg/L of soluble La in the culture solution. It suggests that persistent applications of REEs may lead to potential ecological risk in the environment.Combined chemical analyses and biological measurements were utilized to investigate potential toxicological effects and possible mechanisms involved in risk assessment of rare earth elements （REEs） on Viciafaba L. seedlings, which were hydroponically cultivated and exposed to various concentrations of lanthanum （La） for 15 days. The results showed that La contents in both the solution and roots increased with the increase of extraneous La, contributing to hormetic dose responses of superoxide dismutase （SOD）, catalase （CAT）, guaiacol peroxidase （GPX）, ascorbate peroxidase （APX） and endoprotease （EP） isozymes activities, and HSP 70 production enhanced at low doses but suppressed at higher doses of La. These physiological responses constituted antioxidant and detoxification systems against La-induced oxidative stress. The elevated La levels also contributed to oxidatively modified proteins, which were most responsible for subsequent cell death and growth retardation of the roots. By combination of hormetic and traditional threshold dose levels, the threshold dose range was deduced to be 108-195 μg La/g dry weight in the roots, corresponding to 0.90-3.12 mg/L of soluble La in the culture solution. It suggests that persistent applications of REEs may lead to potential ecological risk in the environment.

关 键 词：rare earth elements lanthanum heat shock protein 70 oxidatively modified proteins ISOENZYMES HORMESIS RISKASSESSMENT 

分 类 号：Q945[生物学—植物学] X172[环境科学与工程—环境科学]