ABSTRACT
Every organism is continuously subjected to challenges of both biotic and abiotic origin and struggles to maintain its survival with minimum damage to its development and physiology. Plants are no exception to this, rather have an additional disadvantage of being unable to locomote and avert the unprecedented abiotic stresses. Therefore, over time, they have evolved inherent adaptive mechanisms by which they cope up with stress in a better way. Plants exhibit very intricate and complex stress responses. Plant’s two vital processes of photosynthesis and respiration are deemed as the most crucial physiological functions that directly govern the overall growth of the plant and are also very sensitive to environmental stresses. Abiotic stress including salinity, elevated CO2 , anoxia, drought, high light, heavy metalloids, and extreme temperature impede photosynthesis and respiration by affecting fundamental photosynthetic and respiratory apparatus, structural and regulatory proteins of chloroplast and mitochondria, carrier proteins and complexes of electron transport chain (ETC), photo- and oxidative phosphorylation, and CO2 fixation. Inhibition of photosynthesis further afflicts respiration, thereby compromising plant growth. However, with varying degree of tolerance, plants manifest diverse adaptive responses 120to an array of abiotic stresses. Henceforth, it is exigent to delve deeper into the mechanistic effects of abiotic stresses on plants and to unravel the details of molecular reprogramming employed by the plants to mitigate the potential harms that any kind of stress beholds. This chapter entails the impact of various environmental stresses on photosynthesis and respiration and how these processes get regulated under such unfavorable conditions. A comprehensive awareness of plant responses to stress has realistic and practical implications for designing effective stress management techniques to ensure proper crop management and food security.
