Arsenic-induced root growth inhibition in mung bean (Phaseolus aureus Roxb.) is due to oxidative stress resulting from enhanced lipid peroxidation

• Published in: Plant growth regulation Vol. 53; no. 1; pp. 65 - 73
• Main Authors: Singh, Harminder Pal, Batish, Daizy R, Kohli, Ravinder Kumar, Arora, Komal
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.09.2007; Springer Nature B.V
• Subjects: Antioxidant enzymes; Antioxidants; Arsenic; Conjugated dienes; Electrolyte leakage; Ferns; lipid peroxidation; Oxidative damage; Oxidative stress; Peroxidation; Phaseolus aureus; Plant growth; Root oxidizability; Seedlings; Vigna radiata var. radiata
• ISSN: 0167-6903; 1573-5087
• DOI: 10.1007/s10725-007-9205-z

Arsenic (As) toxicity and its biochemical effects have been mostly evaluated in ferns and a few higher plants. In this study, we investigated the effect of As (10.0 and 50.0 μM) on seedling growth, root anatomy, lipid peroxidation (malondialdehyde and conjugated dienes), electrolyte leakage, H₂O₂ content, root oxidizability and the activities of antioxidant enzymes in mung bean (Phaseolus aureus Roxb.). Arsenic significantly enhanced lipid peroxidation (by 52% at 50.0 μM As), electrolyte leakage and oxidizability in roots. However, there was no significant change in H₂O₂ content. Arsenic toxicity was associated with an increase in the activities of superoxide dismutase (SOD), guaiacol peroxidase (GPX) and glutathione reductase (GR). In response to 50.0 μM As, the activities of SOD and GR increased by over 60% and 90%, respectively. At 10.0 μM As, the activity of ascorbate peroxidase (APX) increased by 83%, whereas at 50.0 μM it declined significantly. The catalase (CAT) activity, on the other hand, decreased in response to As exposure, and it corresponded to the observed decrease in H₂O₂ content. We conclude that As causes a reduction in root elongation by inducing an oxidative stress that is related to enhanced lipid peroxidation, but not to H₂O₂ accumulation.