Responses and management of heat stress in plants

On the eve of global climate change, temperature increase, is the most evident phenomenon. This temperature increase is posing severe threat for sustainable crop production in many countries across the globe in the form of heat stress. Plants respond in many ways to the prevailing high temperature environment, and several inter and intraspecific differences are reported. Heat stress produces quite tangible changes at cell, tissue, and organ levels. Photosynthetic acclimation to heat stress, synthesis and accumulation of primary and secondary metabolites, induction of stress proteins are among the major adaptive responses to heat stress. The important genes expressed in response to heat stress include heat shock protein (hsp) genes, dehydrins (dhn), senescence-associated (sag) genes, stay-green (sgr) genes. As mechanisms of heat stress tolerance, plants display the maintenance of membrane stability, scavenging of ROS, production of enzymatic and nonenzymatic antioxidants and adjustment of compatible solutes. Plant thermotolerance can be improved by various means; major being the mass screening and morphological and biochemical markers-assisted selection, identification, and mapping of QTLs conferring heat resistance, conventional and molecular breeding, and exogenous use of osmoprotectants and stress-signaling agents. Although pretty well understood, more research efforts are required to understand novel aspects of heat tolerance including molecular cloning and characterization of genes/proteins and understanding the basis of growth improvements with seed pretreatments and plant acclimations. In this chapter, we discuss the plant responses to high temperature stress and integrated approaches, such as genetics, breeding and management options to improve the resistance in plants against heat stress.