ABSTRACT
The underlying mechanisms of Si for improving the resistance in plants to salt stress include maintenance of plant water status, reduction in Na+ uptake, improvement of the K+/Na+ ratio, maintenance of the nutrient balance, promotion of the photosynthetic rate, regulation of the levels of endogenous plant hormones, alteration of the transpiration rate, and mitigation of the toxicity of other heavy metals. Si application has also been found to improve the defensive system of plants by producing antioxidants, which sequentially detoxify the reactive oxygen species (ROS). These physiological and morphological improvements in plants have proved the Si role in the mitigation of salt stress. Recent studies with monocots have shown that Si accumulation in plants is mediated by specific transporters. Here, in this chapter, we summarize the agronomic, physiological/biochemical, and genetic/proteomic responses of different crop genotypes in the alleviation of salt stress as a result of Si supply. Further, advancements with a combination of molecular and genetic studies on Si transport and functions in different crop genotypes will help advance understanding of its complete role under abiotic stress conditions like salinity.
