Silicon supplementation as a promising approach to induce thermotolerance in plants: current understanding and future perspectives

Abstract

In the current situation of climate change, heat is the foremost abiotic stress that is fueling food insecurity by reducing crop production, especially in arid regions around the globe. Therefore, ecofriendly and sustainable solutions are needed to address this challenge. Recent findings have established silicon (Si) as an important stress reliever element in plants which tremendously improves their health under different environmental constraints. Exogenous application of Si via fertigation, foliar spray, or seed priming acts as a booster for the already existing defense machinery of plants to cope with the drastic effects of heat. Si fertigation also improves soil properties including its water holding capacity which indirectly aids to improve plant health. Rhizospheric microorganisms also contribute by increasing the bioavailability of Si in soil. Thus, versatile interactions of Si with soil, plant, and microbes modulate the micro-environment of plants exposed to heat stress which help in mitigating the heat-induced damage to plant growth and fertility. In this review, we focus on the elucidation of the role of Si in heat tolerance at the molecular level. Silicon-derived improvements in various morpho-agronomic, physiological, biochemical, anatomical, and molecular parameters have been discussed in detail. Si-uptake and transport mechanism has been addressed. We have also discussed the knowledge gaps and scope of Si as a biostimulant for future-oriented sustainable agriculture.