| Ground-level ozone has been well established as a phytotoxant responsible for substantial decreases in crop yields. Spatial and temporal ozone trends affecting the Peterborough area were investigated in light of elevated ozone concentrations reported in the region. Ambient ozone concentrations in the Peterborough area resulted in foliar injury to the model plant Phaseolus vulgaris L. cv. Envoy during the 2003 and 2004 growing seasons. However, exposure to similar ozone concentrations during growth chamber experiments did not cause foliar injury. Ozone exposure in the chambers did cause significant changes in shoot length, leaf area, leaf thickness and stomatal conductance. Foliar flavonoid compounds were also examined, but the responses to ozone were variable. It was concluded that ambient ozone concentrations experienced in the Peterborough region are sufficient to elicit a plant responses and, in combination with other stressors, can cause phytotoxic effects, as demonstrated by the appearance of foliar injury.;Key words: ozone, white bean, Peterborough, back trajectory, flavonoids, quercetin, kaempferol, foliar injury, stomatal conductance. |
