Photosynthesis and Associated Aspects Under Abiotic Stresses Environment

Abstract

Abiotic stresses are the prime reason of crop loss worldwide, reducing average yields for most of the major crop plants by more than 50%. Plants as sessile organisms are persistently exposed to changes in environmental conditions. When these changes are swift and extreme, plants generally perceive them as stresses. However stresses are not necessarily a problem for plants because they have evolved effective mechanisms to avoid or reduce the possible damages. The response to changes in environment can be rapid, depending on the type of stress, and can involve adaptation mechanisms, which allow them to survive the adverse conditions. Extreme environmental conditions, such as high and low temperatures, waterlogging and deficits, salinity, and carbon dioxide (CO2) and ozone (O3) concentrations at the leaf surface strongly affect plant growth and development. Such abiotic stresses adversely affect on physiological mechanisms associated with plant responses, adaptation, and tolerance to stresses in terms of photosynthetic mechanisms, such as CO2 diffusion through stomatal control, photosystem II repair, ribulose bisphosphate carboxylase/oxygenase (Rubisco) activity, and generation of reactive oxygen species (ROS), are susceptible to damage that causes great diminution in photosynthetic efficiency. Therefore, photosynthesis is one of the key processes to be affected by abiotic stresses, which results in decrease in CO2 diffusion to the chloroplast and metabolic constraints. Although several structural and functional components of the photosynthetic apparatus are responsive to abiotic stresses, photosystem II (PS II) and Rubisco act as the major stress sensors. In addition, it is essential to systematize current knowledge on the complex network of interactions and regulation of photosynthesis in plants exposed to abiotic stresses. In this chapter, we brought the update knowledge emphasizing on the regulation of photosynthesis and associated aspects that are affected by various abiotic stresses.