Document Detail

Biological detection and analysis of mercury toxicity to alfalfa (Medicago sativa) plants.
MedLine Citation:
PMID:  17905409     Owner:  NLM     Status:  MEDLINE    
Mercury has become one of the major causes of toxic metal pollution in agricultural lands. Accumulation of mercury by plants may disrupt many cellular functions and block growth and development. To assess mercury toxicity, we performed an experiment focusing on the responses of alfalfa (Medicago sativa) to Hg(2+)-induced oxidative stress. Alfalfa plants were treated with 0-40microM HgCl(2) for 7d. The concentrations of Hg(2+) were positively correlated with the generation of O2- and H(2)O(2) in leaves. Treatment with Hg(2+) increased the activities of NADH oxidase and lipoxygenase (LOX) and damaged the biomembrane lipids. To understand biochemical responses under Hg stress, activities of several antioxidant enzymes, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) were assayed. Analysis of SOD activity by non-denaturing polyacrylamide gel electrophoresis revealed five isoforms in leaves, but they showed different patterns. Also, eight isoenzymes of APX and seven of POD in leaves were detected. However, only one isoform of CAT was visualized. The total activities of APX, POD and CAT were generally enhanced. We also measured several antioxidative metabolites such as ascorbate and glutathione (GSH), and found that both differentially accumulated in leaves. These results indicate that the increased levels of O2- and H(2)O(2) under Hg stress were closely linked to the improved capacity of antioxidant enzymes. The data not only provide the important information for better understanding of the toxic and tolerance mechanisms, but as well can be used as a bio-indicator for soil contamination by Hg.
Zhao Sheng Zhou; Shao Jing Wang; Zhi Min Yang
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Publication Detail:
Type:  Journal Article     Date:  2007-10-01
Journal Detail:
Title:  Chemosphere     Volume:  70     ISSN:  0045-6535     ISO Abbreviation:  Chemosphere     Publication Date:  2008 Feb 
Date Detail:
Created Date:  2008-01-15     Completed Date:  2008-04-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0320657     Medline TA:  Chemosphere     Country:  England    
Other Details:
Languages:  eng     Pagination:  1500-9     Citation Subset:  IM    
Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China.
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MeSH Terms
Antioxidants / metabolism
Environmental Pollutants / toxicity
Glutathione Reductase / metabolism
Hydrogen Peroxide / metabolism
Medicago sativa / drug effects*,  metabolism*
Mercury / toxicity*
Oxidative Stress / drug effects
Peroxidases / metabolism
Plant Leaves / drug effects,  metabolism
Reactive Oxygen Species / metabolism
Superoxide Dismutase / metabolism
Time Factors
Reg. No./Substance:
0/Antioxidants; 0/Environmental Pollutants; 0/Reactive Oxygen Species; 7439-97-6/Mercury; 7722-84-1/Hydrogen Peroxide; EC 1.11.1.-/Peroxidases; EC peroxidase; EC Dismutase; EC Reductase

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