Emerging significance of silicon in abiotic stress tolerance: a review

Earth’s crust is rich in silicon (Si) and it is ranked as the second most prevalent element. Si accessibility at the soil-plant interface can enhance 10% of the total dry weight of the plant. Si, as a metalloid, is employed as a fertiliser in soil to stimulate plant growth, alleviate toxic effects imparted by different abiotic stresses like temperature extremes, drought stress, salt stress, heavy metal stress, etc., on plants. This review evaluates current knowledge of Si uptake, transport mechanism and its absorption, role in alleviation of abiotic stress in plants by modulating reactive oxygen species (ROS) generation via altering the antioxidant defense system. This review is also intended to give a preview of current advances in exogenous application of Si and its effect on stress physiology and nutritional balance. This review identifies the knowledge gaps and future directions for the integration of Si into sustainable agricultural systems facing abiotic stresses.