Although silicon is the most recently confirmed essential element for plants life, its deposition mechanism in plants has not been understood. Silica phytoliths were isolated from rice leaves and stems with traditional wet ashing or natural precipitation after cryogenic comminution methods, dissolved in HF solution, centrifuged and then separated a series of cell wall matter with NaOH solution to investigate organic constitution and the related chemical properties that could induce silicon deposition. The results showed that silica phytoliths from wet ashing did not contain organic matter capable of inducing silica deposition, but silica phytoliths obtained by natural precipitation contained two components which resulted in the formation of silica particles. One was the mixture of alkaline polypeptide and phenols from NaOH extract, and the other was acidic protein from HF extract, which had a composition of 14.4 kD molecular weight similar to protein in diatom involved in silica deposition. The acidic protein had different induction amount of silica deposition under different pH, with the greatest at about 5.%硅是最新确认的植物必需元素,但硅在高等植物中的沉积机理尚未揭示.以新鲜水稻茎、叶为材料,分别采用传统湿法灰化和低温粉碎自然沉降法分离出植硅石,HF溶液溶解、离心后用NaOH等溶液对沉淀物逐级分离、提取,得到一系列碱性有机物质,上清液层析脱盐后得到酸性蛋白质；将各组分分别与硅溶液进行反应.结果表明传统湿法灰化提取水稻植硅石不舍有能够沉淀硅的物质,低温粉碎自然沉降法提取的植硅石含有两种组分能够诱导形成硅沉淀.这两种物质分别为来自HF提取液中的酸性蛋白和来自NaOH提取液的碱性多肽与酚类混合物.酸性提取液中舍有相对分子质量约为14.4 kD的蛋白质,与硅藻沉淀硅的蛋白相对分子质量近似.不同酸碱度下酸性蛋白对硅的沉积量不同,以pH 5左右诱导量最大.
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