Air Pollution and Its Role in Stress Physiology

Environment plays a crucial role in the physiological processes of plants. The numerous biotic and abiotic stresses in the plant habitat trigger complex responses in vital processes like photosynthesis, respiration and stomatal function. In this chapter we discuss the effect of various air pollutants on the stress physiological parameters. These studies are crucial because one of the major responses to plant pollutants is the inhibition of photosynthesis. This inhibition of photosynthesis not only alters the growth pattern and longevity but also changes plant phenology. Besides, assimilation of pollutants into the plant processes ultimately leads to their inclusion in the animal community. All this leads to a vicious cycle wherein the ecological factors suppress plant growth and in turn plants hamper the ecology. In this chapter we have also reviewed and highlighted the mechanistic aspect of the pollutants on the vital physiological parameters. The major pollutants which are emphasized are sulphur dioxide (SO2), nitrogen oxides (NOx) and ozone (O3) while physiological parameters reviewed are stomatal conductance, photosynthesis and respiration and photorespiration. These physiological processes are important parameters in governing growth and health of plants. Because all the natural processes are cyclic in nature, it is pertinent to observe that the stress in plants caused by the pollutants also directly and indirectly affects the human population.