A time course assessment of changes in reactive oxygen species generation and antioxidant defense in hydroponically grown wheat in response to lead ions (Pb2+)
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We examined the effect of Pb2+ (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. Pb2+ 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, H2O2, 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 Pb2+-induced oxidative damage in wheat roots involve greater H2O2 accumulation and the deactivation of the related scavenging enzymes.
KeywordsPb toxicity H2O2 accumulation Histochemical detection Membrane integrity ROS generation Antioxidant enzymes
Gurpreet Kaur is thankful to University Grants Commission, New Delhi, India for the financial assistance in the form of research fellowship.
Conflict of interest
The authors declare that they have no conflict of interest.
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