The Role of Silicon in Abiotic and Biotic Stress Conditions

Abstract

In this study, the role of silicon (Si) in the mechanisms developed by plants in response to adverse environmental factors (abiotic and biotic) was investigated. Silicon is taken up in the form of the anion Si(OH)<inf>4</inf> with active or passive absorption by plants. Si accumulating in roots, leaves or husk under abiotic stress conditions prevents water stress by reducing transpiration by means of polymerizing in the form of silicic acid. Generating Al, Fe, Mn, Cd, Pb etc complexes in the soil solution with silicon reduces the potential heavy metal toxicity. The silicon increases the strength and rigidity of the plant stem increasing the thickness of the cell wall. It also suppresses reactive oxygen species (H<inf>2</inf>O<inf>2</inf>,1O<inf>2</inf> and O<inf>3</inf>) which cause peroxidation of lipids in the cell by increasing the superoxide dismutase activity (SDA) of the leaves inducing ethylene (C<inf>2</inf>H<inf>4</inf>). It stimulates or accelerates the activation of sitinase, peroxidase, polyphenol oxidase under biotic stress conditions. Especially in the case of phytopathological diseases or entomological damages, silicon can reduce these damages forming low molecular weight compounds having flavonoids and antifungal properties in dicotyledonous and monocotyledonous plants. © 2017, Centenary University. All rights reserved.