Silicon in Plants: Alleviation of Metal(loid) Toxicity and Consequential Perspectives for Phytoremediation

Abstract

For the majority of higher plants, silicon (Si) is considered a beneficial element because of the various favorable effects of Si accumulation in plants that have been revealed, including the alleviation of metal(loid) toxicity. The accumulation of non-degradable metal(loid)s in the environment strongly increased in the last decades by intensified industrial and agricultural production with negative consequences for the environment and human health. Phytoremediation, i.e., the use of plants to extract and remove elemental pollutants from contaminated soils, has been commonly used for the restoration of metal(loid)-contaminated sites. In our viewpoint article, we briefly summarize the current knowledge of Si-mediated alleviation of metal(loid) toxicity in plants and the potential role of Si in the phytoremediation of soils contaminated with metal(loid)s. In this context, a special focus is on metal(loid) accumulation in (soil) phytoliths, i.e., relatively stable silica structures formed in plants. The accumulation of metal(loid)s in phytoliths might offer a promising pathway for the long-term sequestration of metal(loid)s in soils. As specific phytoliths might also represent an important carbon sink in soils, phytoliths might be a silver bullet in the mitigation of global change. Thus, the time is now to combine Si/phytolith and phytoremediation research. This will help us to merge the positive effects of Si accumulation in plants with the advantages of phytoremediation, which represents an economically feasible and environmentally friendly way to restore metal(loid)-contaminated sites.

Efficient Adsorbent Derived from Phytolith-Rich Ore for Removal of Tetracycline in Wastewater

“…Biochar is widely used for the preparation of adsorbents; however, its carbonization process often leads to the production of pollutant gases . Phytolith is a noncrystalline mineral in living plants through silica deposition of cell walls, fillings of cell lumen, and intercellular spaces of the cortex near evaporating surfaces within plant tissue when the roots absorb dissolved silicon (monomeric silicic acid). , Phytolith in plants has been shown to have the potential for phytoremediation of soils . Phytolith is composed mainly of silica with a small amount of carbon, which combines the benefits of silica and biochar as adsorbents.…”

“… 27 , 28 Phytolith in plants has been shown to have the potential for phytoremediation of soils. 29 Phytolith is composed mainly of silica with a small amount of carbon, which combines the benefits of silica and biochar as adsorbents. Thus, phytoliths can be used as suitable raw materials for the preparation of minerals and biomass adsorbents.…”

Silicon’s Influence on Polyphenol and Flavonoid Profiles in Pea (Pisum sativum L.) under Cadmium Exposure in Hydroponics: A Study of Metabolomics, Extraction Efficacy, and Antimicrobial Properties of Extracts

“…Silicon supplementation enhances nutrient uptake and utilization in pea plants, contributing to their overall health and robustness. Various forms of silicon, such as sodium silicate (Na 2 SiO 3 ), silicic acid (H 2 SiO 4 ), colloidal silica gel (SiO 2aq ), and organosilicon compounds, are utilized in plant supplementation research to improve silicon’s bioavailability. , However, the specific effects of Si supplementation on pea plants, particularly regarding its influence on the content of bioactive compounds, remain understudied. Investigating the optimal concentrations of Si compounds for peas and their potential to mitigate Cd uptake are crucial for reducing health risks associated with pea consumption and developing sustainable agricultural practices.…”