PHOTOSYNTHESIS AND STOMATAL RESPONSES TO POLLUTED AIR, AND THE USE OF PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES FOR EARLY DETECTION AND DIAGNOSTIC-TOOLS

Important physiological processes, like photosynthesis, respiration, the stomatal mechanism, phloem loading, and carbon allocation, are all known to be affected by air pollution. A wide range in sensitivity in physiological responses to SO2, NOx, O3, acid precipitation, and HF is evident from the literature. Some of this variation is clearly because of genetic factors, though much of it is in response to differences in environmental conditions both prior to, during, and after pollutant exposure. Recognizing the importance of the environment, this chapter provides an overview of different fumigation methods and discusses their relevance. It deals on direct effects of SO2, NOx, O3, and acid precipitation on photosynthesis, respiration, and stomata, under the influence of climate and exposure strategies: short-term, long-term, single gas, and mixed gases. As the physiological and biochemical responses are key factors to the health of plants, they may be used as diagnostic tools for predicting injury by air pollution and general stress to individual species and the decline of whole populations. The chapter concludes with an evaluation of such methods of bioindication, because they could be of great relevance to the future and ongoing battle to diminish the deterioration of the physical and biological environment. © 1991 Academic Press Inc.