Mechanisms of silicon-mediated alleviation of abiotic stresses in higher plants: A review

Abstract

Although silicon (Si) is the second most abundant element both on the surface of the Earth's crust and in soils, it has not yet been listed among the essential elements for higher plants. However, the beneficial role of Si in stimulating the growth and development of many plant species has been generally recognized. Silicon is known to effectively mitigate various abiotic stresses such as manganese, aluminum and heavy metal toxicities, and salinity, drought, chilling and freezing stresses. However, mechanisms of Si-mediated alleviation of abiotic stresses remain poorly understood. The key mechanisms of Si-mediated alleviation of abiotic stresses in higher plants include: (1) stimulation of antioxidant systems in plants, (2) complexation or co-precipitation of toxic metal ions with Si, (3) immobilization of toxic metal ions in growth media, (4) uptake processes, and (5) compartmentation of metal ions within plants. Future research needs for Si-mediated alleviation of abiotic stresses are also discussed.

Silício na nutrição mineral e acúmulo de alumínio em plantas de arroz de terras altas

“…Ainda com relação ao Fe e Mn, o Si pode diminuir a toxidez por Fe e Mn, em plantas de arroz (Liang et al 2007). Mesmo não ocorrendo toxidez por esses micronutrientes no experimento, pode ser que, com a aplicação de Si, tenha sido diminuída a absorção de Fe e Mn.…”

Atributos qualitativos de sementes de algodoeiro hidrocondicionadas em soluções de silício

“…Embora o Si não seja considerado elemento essencial às plantas, alguns autores têm verificado efeitos benéficos desse elemento no desenvolvimento dos vegetais (Liang et al, 2007;Cunha et al, 2008;Ma & Yamaji, 2008;Accioly et al, 2009;Guntzer et al, 2012).…”

Effects of silicon on copper toxicity in Erica andevalensis Cabezudo and Rivera: a potential species to remediate contaminated soils

“…1 Liang et al 2 proposed that according to the new definition of essentiality of elements, 3 silicon would be considered an essential element. Silicon is never found in a free form and is always combined with other elements.…”

“…4,5,9 In general graminaceous plants and monocots tend to uptake much more Si than other species. 2,5 These species possess Si active uptake systems, 10 whilst the majority of species accumulate Si via passive diffusion following the water flux driven by transpiration. 8 Silicon accumulation and physiology have been extensively studied in grasses.…”

“…Alleviation of toxicity by Si in plants under abiotic stresses might be a consequence of both internal and external mechanisms. 2 In Cd stressed plants, silicon inhibits Cd transport from roots to shoots, resulting in reduction of Cd content in cell organelle fractions of leaves and the stimulation of antioxidative enzymes. 23 No studies are available on the effect of Si in the response of heathers like E. andevalensis to Cu toxicity.…”