Participation of Phytohormones in Adaptation to Salt Stress

Abstract

Salt stress is one of the major abiotic stresses limiting productivity and quality of agricultural crops. The adverse effects concern germination, plant vigor, and crop yield in arid and semiarid regions. Most crops are salinity sensitive or even hypersensitive and they are described as glycophytes. In contrast, high salinity is tolerated by halophytes, which are present in very small numbers, accounting for approx. only 1 % of the world's fl ora. Glycophytes develop some adaptation mechanisms to monitor salt stress and regulate plant physiology and metabolism in order to cope with this stress. Phytohormones are recognized as vital agents in the adaptation process during salt stress. Plant hormones including abscisic acid, salicylic acid, jasmonic acid, ethylene, brassinosteroids, and the others can regulate that cross talk and responses to salt stress. Molecules, such as transcription factors and MAP kinases, are main agents involved in stress signaling pathways and phytohormone cross talk. This chapter provides an explanation of the salt stress mechanism, while salt stress tolerance and the roles of different plant hormones are presented. The effects of endogenous and exogenous phytohormones on adaptation to salt stress are characterized.

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