Biomineralization describes the pathway of nature to organize inorganic compounds and molecules for the creation of functional systems. This work is part of the DFG special program 1117 'Principles of Biomineralization', which is a multidisciplinary work between scientists from several German universities and also from other European countries. One part is the study of the silicon accumulation in wheat (Triticum aestivum L.) and orchard grass (Dactylis glomerata L.). The plant samples grow under defined conditions in a pot trial. The plant habit and the quantity of biomineralized silica depend on the supplied additives, their availability for the plant and the growth conditions. Investigations were performed with SEM, conventional light microscopy, XRD as well as AAS for quantitative and qualitative elemental analysis. (c) 2005 Published by Elsevier B.V.