title: Toxicological effects, mechanisms, and implied toxicity thresholds in the roots of Vicia faba L. seedlings grown in copper-contaminated soil.
abstract: Copper (Cu) contamination has become a global concern because of industrial, agricultural, and other anthropogenic activities. In the present experiments, the toxicological effects, mechanisms, and potential toxicity thresholds were investigated in the roots of Vicia faba L. seedlings that were cultivated in Cu-amended soils (0, 6.25, 12.5, 25, 50, 100, 200, 400, and 600 mg kg(-1)) for 20 days, based on an analysis of the soil physicochemical properties, native Cu, available Cu, and root-enriched Cu contents. The superoxide dismutase (SOD), ascorbate peroxidase (APX), and guaiacol peroxidase (POD) isozymes and activities, as well as glutathione (GSH) and heat shock protein 70 (HSP70), changed like biphasic dose-response curves, cooperating to control the redox homeostasis. The APX and POD enzymes exhibited enhanced activities and became H2O2 scavengers primarily when the catalase (CAT) activities tended to decrease. Endoprotease (EP) isozymes and activities might be enhanced to degrade carbonylated proteins and alleviate metabolic disturbance in the roots. Additionally, HSP70 may not be suitable as a biomarker for relatively higher soil Cu concentrations and relatively longer exposure times for the roots. As a result, the isozymes and activities of SOD, CAT, and EP, as well as GSH, can be adopted as the most sensitive biomarkers. The toxicity threshold is estimated as 0.76-1.21 mg kg(-1) of available Cu in the soils or 25.04-36.65 μg Cu g(-1) dry weights (DW) in the roots.
authors.affiliation: Jiangsu Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science & Technology, Nanjing, 210044, China.
authors.forename: Xianghua
authors.initials: X
authors.lastname: Xu
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: Huang
authors.forename: Chengrun
authors.initials: C
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Zhong
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tian
authors.forename: Dongdong
authors.initials: D
authors.lastname: Li
authors.forename: Gaojian
authors.initials: G
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Shi
mesh_terms: D060387:Ascorbate Peroxidases / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D003300:Copper / Q000032:analysis / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D054750:Ecotoxicology; D005978:Glutathione / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects*; D036226:Seedlings / Q000187:drug effects* / Q000254:growth & development; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism; D031307:Vicia faba / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism
chemical_list: D018840:HSP70 Heat-Shock Proteins; D012987:Soil; D012989:Soil Pollutants; D003300:Copper; D006861:Hydrogen Peroxide; C121048:guaiacol peroxidase; D060387:Ascorbate Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D005978:Glutathione