ABSTRACT
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Silicon is an element that ranks second on the whole Earth in terms of its abundance. It is accumulated by plants at a level equivalent to that of macronutrient elements such as calcium, magnesium, and phosphorous. Instead of their high accumulation in plants, Si does not come in the category of essential elements of higher plants because its essentiality has not been proven yet. However, the reason behind the increasing attention toward silicon is due to its beneficial effects on plant growth and development, particularly for those plants that are subjected to various biotic (plant diseases and pests) and abiotic stresses (salt and heavy metal toxicity). Moreover, those plants that are growing in soil medium uptakes silicon, but their concentrations vary among the plants around 0.1%–10% (w/w). In addition to this, plants are majorly categorized into three types: (i) excluder species, (ii) intermediate type, and (iii) silicon accumulator. Relatively more attention has been paid to the roles of silicon in inducing disease resistance and alleviating heavy metal toxicity. However, its role under nutrient-deficient conditions remains less focused. Therefore, in this chapter we review the role of Si in enhancing the availability of various nutrients, considering both the extrinsic and intrinsic factors, to mitigate their deficiency in plants.
