硅广泛而大量地分布在自然界,占地壳总重量的26％;在土壤中硅的平均含量为33％。它不以游离状态存在,而常与氧结合成二氧化硅或硅酸盐,是许多宝石(如水晶、碧玉、玛瑙等)和普通岩石矿物(如花岗岩、玄武岩、石英、云母、长石、辉石、角闪石等)的主要成分。岩石风化后形成土壤母质,并产生大量粘土矿物,如高岭石、蒙脱石等,给土壤带来保持水分与养分的能力,为植物生长创造了必要的条件。 硅在整个植物界的分布是极不均匀的,大体上说,比较原始的植物,如硅藻之类的单细胞藻类、苔藓植物、羊齿植物含硅量比进化程度较高的被子植物多,在被子植物中单子叶植物比双子叶植物多。有些植物能大量吸收和累积硅酸(例如水稻茎叶和硅藻细胞中可高达20％),被称为硅酸植物。硅酸植物的特征不仅是硅含量高,而且钙含量低,其Si/Ca比值显 Silicon is widely and abundantly distributed in nature, accounting for 26% of the total weight of the crust; the average content of silicon in the soil is 33%. It is not free state, and often combined with oxygen into silica or silicate, many gems (such as crystal, jasper, agate, etc.) and ordinary rock minerals (such as granite, basalt, quartz, mica, feldspar, Pyroxene, hornblend, etc.) of the main components. After the weathering of the rock, the soil parent material is formed and a large amount of clay minerals, such as kaolinite and montmorillonite, are generated, giving the soil the ability to retain moisture and nutrients, thereby creating necessary conditions for plant growth. The distribution of silicon throughout the plant kingdom is extremely heterogeneous. In general, more primitive plants, such as single-cell algae such as diatoms, bryophytes, and fern plants contain more silicon than angiosperms that have a higher degree of evolution , More monocots in angiosperms than dicotyledons. Some plants can absorb and accumulate silicic acid in large quantities (for example up to 20% in rice stems and diatoms), known as silicic acid plants. Silicate plants are characterized not only by their high silicon content but also by their low calcium content and their Si / Ca ratio