ENVIRONMENTAL FACTORS AFFECTING THE HEAT STABILITY OF THE PHOTOSYNTHETIC APPARATUS

Abstract

Owing to greenhouse effect and severe dry periods in the agricultural fields, cultivated plants are increasingly exposed to the adverse impact of several abiotic stresses. Therefore, an increasing emphasis should be placed on how multiple stresses affect the physiological processes in plants and how plants respond to the coexistence of combined stress factors. Simultaneous environmental factors may elicit a response different from that given to a single factor, resulting in intensification, overlapping or antagonistic effects. Although the rate of photosynthesis is significantly reduced by salinity and decreased water availability, the thermotolerance of the photosynthetic apparatus may be altered by salt and drought preconditioning. In this short review, we focused on the individual effect of heat stress and the influence of dehydration and NaCl treatment on the heat tolerance of plants. According to our present knowledge, the thermostability of the photosynthetic apparatus may usually be improved by pretreatment of drought or NaCl. At the same time, several different mechanisms in the background of the higher thermostability are hypothesized. These possible drought- and salt-induced processes are also summarized by this review article.