Manipulation of silicon metabolism in plants for stress tolerance

Silicon (Si) being considered as a nonessential element for plant growth and development finds its role in providing several benefits to the plant, especially under stress conditions. Thus Si can be regarded as a “multitalented” quasiessential element. It is the most abundant element present in the earth’s crust after oxygen predominantly silicon dioxide (SiO2), form plants cannot utilize. Plants take up Si into their root from the soil in the plant-available forms (PAF) such as silicic acid or mono silicic acid [Si(OH)4 or H4SiO4]. Nevertheless, besides being abundantly available, the PAF of Si in the soil is mostly a limiting factor. To improve Si-uptake and derived benefits therein in plants, application and manipulation of silicon sources are of great importance. In this chapter, we will discuss the role of silicon in plant metabolism under stressful conditions. Moreover, the manipulation of silicon sources to boost plant metabolic activity will also be discussed.