Silica is present in soil and culture solutions as undissociated monosilicic acid (H4Si04) and this suggests that its uptake by plants would be a passive, non-selective process. We have earlier reported (Jones and Handreck 1965) that the overall uptake by oats (Avena sterilis cv. Algerian) can be accounted for simply in terms of the concentration of monosilicic acid in the soil solution and the amount of water transpired. Thus, when grown in two potted soils containing 7 and 67 p.p.m. Si02 in solution, oat plants at maturity contained 28 and 274 mg Si02 per plant respectively, having transpired 3·9 litres of water and produced 7·0 g of dry matter. The concentration of silica in xylem sap from oats is similar to that in the external solution. When Trifolium incarnatum (L.) (crimson clover) was grown in these two soils the plants had transpiration ratios of 510-530 but contained silica in concentrations which were only 5-10% of those in oats. This suggests that T. incarnatum has some means of excluding silica from the tops; we have examined this further by measuring the concentration of silica in the xylem sap.

Silicon (Si), an extremely abundant metalloid in the Earth’s crust, is increasingly recognized as a beneficial element for plants, particularly under escalating abiotic and biotic stresses associated with climate change. This review synthesizes current knowledge on the role of silicon in agroecosystems, focusing on its physiological functions, uptake and transport mechanisms, stress‐mitigating effects, and application strategies relevant to climate-smart crop production. Plants predominantly absorb silicon as monosilicic acid [Si(OH)₄], with root-to-shoot transport mediated by the Lsi1 influx and Lsi2 efflux transporters, while soil pH, texture, organic matter, and temperature strongly regulate silicon solubility and bioavailability. Silicon supplementation enhances plant performance through cell wall reinforcement via phytolith deposition, improved plant–water relations, and activation of metabolic and transcriptional responses. Consequently, silicon improves seed germination, growth, photosynthesis, gas exchange, photosystem efficiency, and yield across diverse cropping systems. Key mechanisms include aquaporin-mediated increases in root hydraulic conductivity, regulation of abscisic acid signaling and stomatal behavior, osmotic adjustment through compatible solutes, and enhanced antioxidant capacity that mitigates reactive oxygen species–induced damage. Silicon also contributes to salinity tolerance by maintaining Na⁺/K⁺ homeostasis, improves resistance to temperature extr

<p>Plants produce silica in large quantities, up to 2-10% per dry weight, depending on growth conditions and plant species. The roots absorb monosilicic acid from the soil, and it is transported with water and distributed in nearly all plant tissues. With evapotranspiration, the silicic acid solution is concentrated, and eventually silica forms at leaf epidermis. Nonetheless, the distribution of silica deposits is not uniform within plant tissues. This suggests that there are biological processes that control the deposition of the mineral. In a recent work, the protein Siliplant1 (Slp1) was discovered to precipitate silica in plants. Slp1 is expressed in sorghum leaf epidermal cells called silica cells. Biological molecules active in silica formation typically present positive charge moieties and form some 3D aggregation pattern that allows monosilicic acid to condense into bigger organized structures. Slp1 contains a 24 amino acid N-terminal signal peptide, followed by 124 amino acid linking sequence and a 7-repeat sequence. Slp1 without the signal peptide and a short, conserved peptide appearing five times in Slp1 precipitate silica <em>in vitro</em>. However, the activity of other parts of Slp1 in silica precipitation remains unknown. To analyze sequence motifs that precipitate silica, we synthesized segments of the repeating sequence in Slp1, and characterized the precipitation reactions by yield and spectroscopy. Thermal gravimetric and electron microsc

Abstract In the era of climate change, due to increased incidences of a wide range of various environmental stresses, especially biotic and abiotic stresses around the globe, the performance of plants can be affected by these stresses. After oxygen, silicon (Si) is the second most abundant element in the earth’s crust. It is not considered as an important element, but can be thought of as a multi-beneficial quasi-essential element for plants. This review on silicon presents an overview of the versatile role of this element in a variety of plants. Plants absorb silicon through roots from the rhizospheric soil in the form of silicic or monosilicic acid. Silicon plays a key metabolic function in living organisms due to its relative abundance in the atmosphere. Plants with higher content of silicon in shoot or root are very few prone to attack by pests, and exhibit increased stress resistance. However, the more remarkable impact of silicon is the decrease in the number of seed intensities/soil-borne and foliar diseases of major plant varieties that are infected by biotrophic, hemi-biotrophic and necrotrophic pathogens. The amelioration in disease symptoms are due to the effect of silicon on a some factors involved in providing host resistance namely, duration of incubation, size, shape and number of lesions. The formation of a mechanical barrier beneath the cuticle and in the cell walls by the polymerization of silicon was first proposed as to how this element decreases plant dis

radiolaria, secrete skeletal structures made of silica. Silica is deposited in many plant tissues. Owing to the abundance of silicon in the Earth's crust Silicon (, SILL-ih-kən) is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent non-metal (sometimes considered as a metalloid) and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Although silicon is readily available in the form of silicates, very few organisms use it directly. Diatoms, radiolaria, and siliceous sponges use biogenic silica as a structural material for their skeletons. Some plants accumulate silica in their tissues and require silicon for their growth, for example rice. Silicon may be taken up by plants as orthosilicic acid (also known as monosilicic acid) and transported through the xylem, where it forms amorphous complexes with components of the cell wall. This has been shown…

structures of the plant. The silica is absorbed in the form of monosilicic acid (Si(OH)4), and is carried by the plant's vascular system to the cell walls Phytoliths (from Greek, "plant stone") are rigid, microscopic mineral deposits found in some plant tissues, often persisting after the decay of the plant. Although some use "phytolith" to refer to all mineral secretions by plants, it more commonly refers to siliceous plant remains. Phytoliths come in varying shapes and sizes. The plants which exhibit them take up dissolved silica from the groundwa Phytoliths (from Greek, "plant stone") are rigid, microscopic mineral deposits found in some plant tissues, often persisting after the decay of the plant. Although some use "phytolith" to refer to all mineral secretions by plants, it more commonly refers to siliceous plant remains. Phytoliths come in varying shapes and sizes. The plants which exhibit them take up dissolved silica from the groundwater, whereupon it is deposited within different intracellular and extracellular structures of the plant. The silica is absorbed in the form of monosilicic acid (Si(OH)4), and is carried by the plant's vascular system to the cell walls, cell lumen, and intercellular spaces. Depending on the plant taxa and soil condition, absorbed silica can range from 0.1% to 10% of the plant's total dry weight. When deposited, the silica replicates the structure of the cells, providing structural support to the plant. Phytoliths strengthen the plant against abiotic stressors such as salt runoff, metal toxicity, and extreme temperatures. Phytoliths can also protect the plant against biotic threats such as insects and fungal diseases. D… Soluble silica, also called monosilicic or orthosilicic acid with a chemical formula of (Si(OH)4), is taken up from the soil when plant roots absorb groundwater. From there, it is carried to other plant organs by the xylem. By an unknown mechanism, which appears to be linked to genetics and metabolism, some of the silica is then laid down in the plant as silicon dioxide. This biological mechanism does not appear to be limited to specific plant structures, as some plants have been found with silica in their reproductive and sub-surface organs.