Chapter 5 - Silicon-accumulating plants in the plant kingdom

Abstract

The mineral composition of plants varies with the plant species and the growth environment. In the monocot species, the silicon (Si) content is high and the calcium (Ca) content is low. In dicot species, the Ca content is high and Si content is low. Si-accumulating plants can be discriminated from nonaccumulating plants by using two criteria—Si content and Si/Ca ratio. The Si content of 0.5% is used as the critical value. The Si/Ca ratio is used as the second criterion because the plants that accumulate Si tend to have a low Ca concentration. Some monocots, some Pteridophytes, and Bryophytes are Si accumulators. Among the monocots, most Si accumulators belong to Cyperacea and Gramineae family. All species in Lycopsida and Equisetopsida are Si accumulators. All Gramineae species are Si accumulators, but the degree of Si accumulation differs among subfamilies. There are no Si accumulator species in dicots. Si content also varies with the variety in the same species. Si accumulation depends on whether the plant takes up Si or not. Si accumulation is an advantageous trait for plants, and this trait is considered to be preserved.