Abstract

Abiotic stresses like salinity, drought, and high temperature have undesirable effects on crop productivity and quality, and negative trends in sustainable agriculture. The adverse effects of salinization on plants are evident from negative growth trends from alteration or inhibition of biochemical and physiological processes. The ability of plants to tolerate salt stress is determined by multiple biochemical and molecular pathways. Salt accumulation in soil and water prevents plant growth through two major impacts. Firstly, the existence of salt in the soil solution decreases the capacity of a plant to absorb water, which is referred to as the osmotic or water deficiency of salt stress. This impact relies on the concentration of salt outside the plant and growth inhibition is mainly due to water shortage or osmotic stress, with very little genotypic variation in this trait observed. Secondly, the salt-specific or ion-excess salinity impact, whereby the accumulation of Na+ and Cl- ions within the plant leads to toxic impacts on plant biochemistry. Photosynthesis is crucial for the survival of all living biota, playing a key role in plant productivity by generating the carbon skeleton that is the primary component of all biomolecules. Salinity stress is a major threat to agricultural productivity and sustainability as it can cause irreversible damage to photosynthetic apparatus at any developmental stage. This work summarizes the current knowledge of impact of salinity on the key targets of the photosynthetic apparatus under salt stress; and tolerance of PSII to salt stress and its repair; salinity effects on biochemistry of CO₂ fixation and its regulation.

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