ABSTRACT
In experiments where plants were treated with O3 added to charcoal-filtered air, for example, O3 toxicity was found to be greater than in plants exposed to the same concentrations of O3 in nonfiltered air. The sensitivity of plants to O3 differs not only between species, but also between cultivars, provenances, and even individuals within a given species. Concentrations of O3 in Europe were much lower. However, as industrial activity, transport, etc. increased, so did concentrations of O3 and O3-induced injury to plants. In nature, plants are always exposed to variable environmental stresses such as O3. Exposure to other atmospheric pollutants, pesticides or heavy metals, lack of nutrients, or attack by pathogens are normally reflected by enhanced rates of ethylene release. The potential for atmospheric pollutants to damage vegetation has been recognized for centuries.
