Combined Effect of Sulfur Dioxide and Ozone on Bean and Tobacco Plants

摘要

Plants of two cultivars of Phaseolus vulgaris and one cultivar of Nicotiana tabacum were exposed to a replicated series of concentrations of sulfur dioxide (SO2), ozone (03), and combinations of these two air pollutants for single four-hour periods. Experiments were performed in controlled-environment chambers using concentrations of pollutants above and below Federal ambient air quality standards in order to determine whether interactive effects result from exposure to concentrations of pollutants occurring in some agricultural areas of the United States. Dose-response curves for foliar symptoms were found to approximate logarithmic functions of pollutant concentrations when the frequency of leaf injury was converted into probit units. In bean cultivars, the toxicity of SO2 or O3 was either amplified or not affected in the presence of the two pollutants.