Tomato plant growth with continuous exposure to sulphur dioxide and nitrogen dioxide

Abstract

Tomato plants exposed continuously to 0·11 μl litre −1 sulphur dioxide (SO 2) or 0·11 μl litre −1 nitrogen dioxide (NO 2) were not significantly different from control plants in leaf, stem or root fresh or dry weights or leaf area. Exposure to a mixture of SO 2 and NO 2 at these concentrations resulted in significant decreases in leaf fresh weight and area after 14 days and significant decreases in root fresh weight and stem and root dry weight after 28 days. Leaf water concentration decreased markedly in mixture-treated plants while leaf dry weight and stem and root water concentrations were unchanged. The leaves/stem and leaves/root fresh weight ratios decreased in mixture-treated plants while leaves/stem and leaves/root dry weight ratios increased.