High temperature stress in fruit crops

Plants exhibit a variety of responses to high temperatures, which are depicted by symptomatic and quantitative changes in growth and morphology. The ability of the plant to cope with or adjust to the heat stress varies across and within as well as at different developmental stages. Pollen viability, patterns of assimilate partitioning, and growth and development of seed are highly adversely affected.Other notable heat stress effects include structural changes in tissues and cell organelles, disorganization of cell membranes, disturbance of leaf water relations, and impedance of photosynthesis and photosynthetic membranes and lipid peroxidation via the production of ROS and changes in antioxidant enzymes and altered pattern of synthesis of primary and secondary metabolites are also of considerable importance. The induction of signaling cascades leading to profound changes in specific gene expression is considered an important heat-stress adaptation. Developing plants with improved heat tolerance, attempts have been made to induce heat tolerance in a range of plant species using different approaches. These include preconditioning of plants to heat stress and exogenous applications.