Amelioration of sulphur dioxide phytotoxicity in wheat cultivars by modifying NPK nutrients

Field experiments were conducted to examine the responses of two cultivars of wheat (Malviya 206 and Malviya 234) to sulphur dioxide when grown at six different nutrient levels. Thirty-day-old plants were exposed to 0.15 ppm SO2 for 4 hours per day, 5 days per week for 8 weeks. Total plant length was reduced significantly in SO2 treated plants, except those grown using recommended and twice the recommended fertilizer applications. Leaf area, however, was significantly reduced in SO2 treated plants. Total plant biomass and yield also decreased in plants exposed to SO2. Root:shoot ratio and leaf:weight ratio altered in plants grown at different nutrient levels and with different SO2 treatments. Total chlorophyll, ascorbic acid, starch and protein contents were reduced by SO2 exposure whereas total soluble sugar and reducing sugar levels were increased. The level of changes in different parameters due to SO2 exposure varied with different nutrient levels and cultivars of wheat. Soil mineral nutrient status has been found to modify the response of wheat plants. Yield data have suggested that Malviya 234 is more responsive to nutrient status and showed lower reductions due to SO2 exposure. (C) 1997 Academic Press Limited.