Entomologie, Ornithologie und Herpetologie: Aktuelle Forschung
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A Novel Mechanism by Silicon Supplements Defends Grasses Against Herbivores

Calvin Fischer

Silica can constitute 2–6 % of the dry weight of the leaves of grasses, many times higher than is typical in dicotyedonous plants. It is actively taken up as silicic acid from the soil and the majority is deposited as hydrated amorphous silica within the lumen of epidermal cells, forming bodies known as phytoliths, whose shapes are characteristic of individual grass taxa. It has been suggested that phytoliths act as a defence against both vertebrate and invertebrate herbivores by increasing the abrasiveness of grass leaves; they wear down the teeth of herbivores and hence deter feeding. The fossil record supports this, since the evolution of high crowned teeth among the Ungulata, continuously growing teeth among the Rodentia and Lagamorpha, and enlarged mandibles in the Lepidoptera and Orthoptera, have all been linked to a diet of grass Furthermore a diet of silica-rich grass apparently causes microwear scratches on teeth.