Physiological disturbances in plants caused by air pollutants

Abstract

Synopsis The physiological and biochemical features of plants that are responsible for determining susceptibility or tolerance to air pollutants have often proved hard to identify. In recent years, however, there has been new experimental evidence of responses which may be of critical importance. These include (a) changes in stomatal behaviour, affecting plant-water relations, (b) alterations in carbon and nitrogen assimilation and partitioning which can influence root growth, and (c) interference with the processes of winter hardening. Evidence of these changes to physiological processes, and the ways in which responses to pollutants may become more significant to plant survival in the presence of other environmental stresses, are discussed. The longer-term consequences, or secondary responses, such as effects on associations with other organisms, are also briefly reviewed. We have also examined the possibility that ecosystems may be overloaded with inputs of nitrogen from the atmosphere.