Response of hydrogen peroxide scavenging system in two soybean cultivars exposed to SO 2: experimental evidence for the detoxification of SO 2 by enhanced H 2O 2 scavenging components

• Published in: Environmental pollution (1987) Vol. 82; no. 1; pp. 99 - 105
• Main Authors: Rao, M.V., Dubey, P.S.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 1993
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/0269-7491(93)90167-M

The impact of SO 2 on superoxide dismutase (SOD) and the ascorbate-glutathione cycle was investigated in a tolerant (cv. Punjab-1) and a sensitive (cv. JS 7244) cultivar of soybean ( Glycine max (L.) Merr.). In spite of SO 2 stimulated SOD activities in both the cultivars, only cv. JS 7244 has significantly enhanced Malondialdehyde (MDA) contents. This differential resonse was attributed to the ability of cv. Punjab-1 to enhance glutathione reductase (GR) activity and to maintain high GSH/GSSG and ASA/DHA ratios. Post-fumigation analysis indicated the ability of cv. Punjab-1 to maintain SO 2-enhanced antioxidants, whilst they declined in cv. JS 7244 the moment fumigation was terminated. Exposure of SO 2-acclimated plants (cv. Punjab-1) with their enhanced antioxidants to 250 μg m −3 SO 2 for 6 h exhibited no enhanced cellular injury (MDA content) when compared to that of control plants with their normal antioxidant levels. These results indicate a relation between the ability of a plant to maintain reduced glutathione (GSH) and ascorbate (ASA) and SO 2 tolerance, and they also present evidence for the ability of plants, with elevated antioxidants, to tolerate SO 2-induced oxygen-free radical toxicity.