ABIOTIC STRESS PHYSIOLOGY:TEMPERATURE EXTREMES AND FLOODING

Abiotic stresses such as extreme temperatures and flooding are among the most significant environmental constraints limiting plant growth,development and productivity. Plants frequently encounter high or low temperature episodes and waterlogging events due to rapid climatic fluctuations. Their ability to perceive, respond, and adapt to these stresses determines their survival and yield potential. This
chapter synthesizes current knowledge on the physiological,
biochemical, molecular and genetic mechanisms underlying plant responses to temperature extremes and flooding. High temperature stress disrupts membrane integrity, protein stability, photosynthetic efficiency, reproductive processes and carbon assimilation. Plants counteract these effects through adaptive traits, such as protective leaf structures, osmotic adjustments, the accumulation of compatible
solutes, antioxidant defence, and the synthesis of heat shock proteins(HSPs) and chaperones. Molecular studies highlight the central roles of HSFs, HSPs, antioxidants and ubiquitin-mediated protein turnover in thermotolerance, with significant contributions from ABA, SA, ethylene, Ca²⁺, ROS and lipid-based signalling pathways. Overall, this compilation provides a comprehensive overview of the physiological complexities and adaptive strategies plants use under temperature extremes and flooding.