Exposure of plants to higher ambient temperatures results in a complex set of morpho-physiological changes at both the whole and cellular levels. At the whole-plant level, the impact of heat stress is usually perceived as a reduction in plant growth and a decline in photosynthetic carbon assimilation. At the cellular level, heat stress causes protein aggregation and denaturation, enzyme inactivation, loss of membrane integrity and functionality, and organelle dysfunction. Plants respond to high ambient temperatures by activating a plethora of defense mechanisms, which can be categorized into strategies for heat stress avoidance and heat stress tolerance. The avoidance strategy includes all the mechanisms that a plant triggers to prevent excessive heat absorption or exposure, and some of these are leaf orientation, enhanced stomatal conductance, cooling through transpiration, increased leaf thickness, and larger xylem vessels. Heat stress tolerance involves all the mechanisms that enable a plant to maintain its metabolism and physiological processes when it is already experiencing heat stress. These mechanisms include the synthesis of protective molecules such as heat shock proteins, osmotic adjustment to maintain cellular turgor, and the activation of antioxidant systems to counterbalance oxidative stress. Plant acclimation, also known as pre-exposure to heat stress or heat priming, represents a third strategy that helps plants mitigate the harmful effects of heat stress. Advances in understanding all of these defense mechanisms offer essential guidance for developing effective strategies to increase crop resilience to heat stress.
S. Murtić (Mon,) studied this question.