title: Biochemical Adaptations in Zea mays Roots to Short-Term Pb(2+) Exposure: ROS Generation and Metabolism.
abstract: The present study investigated the effect of lead (0, 16, 40 and 80 mg L(-1) Pb2+) exposure for 3, 12 and 24 h on root biochemistry in hydroponically grown Zea mays (maize). Pb2+ exposure (80 mg L(-1)) enhanced malondialdehyde content (239%-427%), reactive carbonyl groups (425%-512%) and H2O2 (129%-294%) accumulation during 3-24 h of treatment, thereby indicating cellular peroxidation and oxidative damage. The quantitative estimations were in accordance with in situ detection of ROS generation (using 2',7'-dichlorodihydrofluorescein diacetate dye) and H2O2 accumulation. Pb2+ treatment significantly reduced ascorbate and glutathione content during 3-24 h of exposure. On the contrary, levels of non-protein thiols were enhanced by 3-11.8 time over control in response to 16-80 mg L(-1) Pb2+ treatment, after 24 h. A dose-dependent induction in ascorbate peroxidase and lipoxygenase enzyme activity was observed in Z. mays roots. The activities of ascorbate-recycling enzymes (dehydroascorbate reductase and monodehydroascorbate reductase) were significantly increased in relation to concentration and duration of Pb2+ treatment. The study concludes that Pb2+-exposure induces ROS-mediated oxidative damage during early period of exposure despite the upregulation of enzymes of ascorbate-glutathione cycle.
authors.affiliation: Department of Environment Studies, Panjab University, Chandigarh, India.
authors.forename: Gurpreet
authors.initials: G
authors.lastname: Kaur
authors.forename: Shubhpreet
authors.initials: S
authors.lastname: Kaur
authors.forename: Harminder Pal
authors.initials: HP
authors.lastname: Singh
authors.forename: Daizy Rani
authors.initials: DR
authors.lastname: Batish
authors.forename: Ravinder Kumar
authors.initials: RK
authors.lastname: Kohli
authors.forename: Valbha
authors.initials: V
authors.lastname: Rishi
mesh_terms: D060387:Ascorbate Peroxidases / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D007854:Lead / Q000494:pharmacology*; D008084:Lipoxygenase / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010088:Oxidoreductases / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects* / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D007854:Lead; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D060387:Ascorbate Peroxidases; D008084:Lipoxygenase; D009247:NADH, NADPH Oxidoreductases; C023927:monodehydroascorbate reductase (NADH); C020666:glutathione dehydrogenase (ascorbate); D005978:Glutathione; D001205:Ascorbic Acid