title: A time course assessment of changes in reactive oxygen species generation and antioxidant defense in hydroponically grown wheat in response to lead ions (Pb2+).
abstract: We examined the effect of Pb(2+) (8 and 40 mg l(-1)) on reactive oxygen species generation and alterations in antioxidant enzymes in hydroponically grown wheat at 24, 72, and 120 h after exposure. Pb(2+) toxicity was more pronounced on root growth, and it correlated with the greater Pb accumulation in roots. Pb exposure (40 mg l(-1)) enhanced superoxide anion, H(2)O(2), and MDA content in wheat roots by 1.9- to 2.2-folds, 56-255%, and 41-90%, respectively, over the control. Pb-induced loss of membrane integrity was confirmed by the enhanced electrolyte leakage and in vivo histochemical localization. Activities of scavenging enzymes, superoxide dismutases and catalases, enhanced in Pb-treated wheat roots by 1.4- to 5.7-folds over that in the control. In contrast, the activities of ascorbate and guaiacol peroxidases and glutathione reductases decreased significantly, suggesting their non-involvement in detoxification process. The study concludes that Pb(2+)-induced oxidative damage in wheat roots involve greater H(2)O(2) accumulation and the deactivation of the related scavenging enzymes.
authors: Department of Environment Studies, Panjab University, Chandigarh, 160014, India.
authors: Gurpreet
authors: G
authors: Kaur
authors: Harminder Pal
authors: HP
authors: Singh
authors: Daizy Rani
authors: DR
authors: Batish
authors: Ravinder Kumar
authors: RK
authors: Kohli
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002413:Cations, Divalent / Q000633:toxicity; D006861:Hydrogen Peroxide / Q000378:metabolism; D007854:Lead / Q000737:chemistry / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014908:Triticum / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002413:Cations, Divalent; D017382:Reactive Oxygen Species; D007854:Lead; D006861:Hydrogen Peroxide