title: Antioxidant defense in a lead accumulating plant, Sesbania drummondii.
abstract: Seedlings of Sesbania drummondii were grown in 500 mg l-1 Pb(NO3)2 in presence and absence of chelators: EDTA, DTPA and HEDTA for 4 weeks. Plants were assayed for activities of the antioxidant enzymes: ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT), superoxide dismutase (SOD) and glutathione (gamma-glutamyl-cysteinyl-glycine) content. Activities of antioxidant enzymes were elevated in the presence of Pb but were similar to controls in plants grown in the presence of Pb and EDTA, -DTPA or -HEDTA. Glutathione content was significantly elevated upon exposure to Pb, but lowered upon exposure to chelators. Chlorophyll a fluorescence kinetics were assessed by determination of Fv/Fm and Fv/Fo values. Seedling growth in Pb alone and Pb + chelators did not significantly affect photosynthetic integrity (Fv/Fo) and efficiency (Fv/Fm). The results suggest that Sesbania plants were able to tolerate Pb-induced stress using an effective antioxidant defense mechanism. This study also indicates a protective role of synthetic chelators in Pb-induced oxidative stress metabolism in a Pb-accumulating plant.
authors.affiliation: Department of Biology, Western Kentucky University, 1 Big Red Way, Bowling Green, KY 42101, USA.
authors.forename: A Thomas
authors.initials: AT
authors.lastname: Ruley
authors.forename: Nilesh C
authors.initials: NC
authors.lastname: Sharma
authors.forename: Shivendra V
authors.initials: SV
authors.lastname: Sahi
mesh_terms: D060387:Ascorbate Peroxidases; D002374:Catalase / Q000378:metabolism; D002614:Chelating Agents / Q000737:chemistry; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D007887:Fabaceae / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D007854:Lead / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D009195:Peroxidase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects / Q000502:physiology*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D002614:Chelating Agents; D002734:Chlorophyll; D007854:Lead; D010544:Peroxidases; C121048:guaiacol peroxidase; D060387:Ascorbate Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D000077194:Chlorophyll A