Silicon enhancement of estimated plant biomass carbon accumulation under abiotic and biotic stresses. A meta-analysis

Abiotic and biotic stresses are the major factors limiting plant growth worldwide. Plants exposed to abiotic and biotic stresses often cause reduction in plant biomass as well as crop yield, resulting in plant biomass carbon loss. As a beneficial and quasi-essential element, silicon accumulation in rhizosphere and plants can alleviate the unfavorable effects of the major forms of abiotic and biotic stress through several resistance mechanisms and thus increases plant biomass accumulation and crop yield. The beneficial effects of silicon on plant growth and crop yield have been widely reviewed over the last years. However, carbon accumulation of silicon-associated plant biomass under abiotic and biotic stresses has not yet been systematically addressed. This review article focuses on both the main mechanisms of silicon-mediated alleviation of abiotic and biotic stresses and their effects on plant biomass carbon accumulation in terrestrial ecosystems. The major points are the following: (1) the recovery of plant biomass via silicon mediation usually exhibits a bell-shaped response curve to abiotic stress severity and an S-shaped response curve to biotic stress severity; (2) although carbon concentration of plant biomass decreases with silicon accumulation, more than 96% of the recovered plant biomass contributes to plant biomass carbon accumulation; (3) silicon-mediated recovery generally increases plant biomass carbon by 35% and crop yield by 24%. In conclusion, silicon can improve plant growth and enhance plant biomass carbon accumulation under abiotic and biotic stresses in terrestrial ecosystems.