[The function of mobile silicon compounds in plants and in the soil-plant system]
2008
Matychenkov, V. V.
Silicic acids were a main research object. Thirteen crops were tested: maize, rice, sorghum, oranges, tomatoes, cucumbers and others. Monosilic acid (MA), oligomers of silicic acid, low- and high-molecular polisilicic acids (PA) are revealed in the plant tissues and in the soils. The plants take up MA actively through their roots and leaves and they have a mechanism of rapid redistribution of silicon (Si) into zones subjected to stress. Si is transported inside a plant mainly in the form of PA. The experiments have proved that optimization of Si nutrition improves plant germination and also it increases plant resistance to unfavorable environment. Raised resistance to drought of the plants with optimal Si supply is explained by PA capability to hold water molecules inside an organism and then to liberate them in the conditions of air or soil drought. MA is able to fix metal ions into mobile complexes and sparingly soluble silicates. Silicic acid anion can replace phosphate anion in sparingly soluble phosphates of Ca, Al and Fe; that is why P accessibility for plants and microorganisms can increase by 30-50%. The main flow of matter is realized in biogeochemical Si cycle of surface ecosystems via MA and PA migration and transformation in the soil-plant system. MA content in this system depends from Si balance in a plant community and PA content depends on mineralogical soil composition, soil density and other chemical and physical properties of solid matter of grounds and soils.
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