Dietrich Dagmar, Hinke Simone, Baumann Wolfgang, Fehlhaber Rüdiger, Bäucker Ernst, Rühle Gebhardt, Wienhaus Otto, Marx Günter
Institute of Chemistry, Technische Universität Chemnitz, Germany.
Anal Bioanal Chem. 2003 Jun;376(3):399-404. doi: 10.1007/s00216-003-1847-8. Epub 2003 Apr 16.
The silica accumulation in orchard grass (Dactylis glomerata L.) and wheat (Triticum aestivum L.) has been studied in plant samples grown under defined conditions in a pot trial. The plant habit and the quantity of biomineralised silica within the selected Gramineae depend to a remarkable extent on the soil. The plants grew with different soil pH values and silica additives. By means of atomic absorption spectrometry, the silicon enrichment in different plant parts was determined. In dried plant parts the silica bodies can be well distinguished by variable pressure scanning electron microscopy in the back scattering mode. They are located in silica cells below the epidermis and in epidermal appendices (bristles, prickle hairs). The silica bodies showed a defined morphology, structure and composition which was elucidated by the combined performance of scanning electron microscopy in combination with X-ray spectroscopy, solid-state nuclear resonance, X-ray diffraction and Raman spectroscopy. The composition was near to stoichiometric SiO(2) (41 weight% silicon, 56 weight % oxygen), and the SiO(4/2)tetrahedra were arranged preferentially in three-dimensional networks; a smaller proportion was in chains and layers. The silica bodies with an overall amorphous structure contained crystalline precipitates, which could be indexed by alpha-quartz.
在盆栽试验中，对在特定条件下生长的果园草（鸭茅）和小麦（普通小麦）中的二氧化硅积累情况进行了研究。所选禾本科植物的植株形态和生物矿化二氧化硅的含量在很大程度上取决于土壤。这些植物在不同的土壤pH值和添加二氧化硅的条件下生长。通过原子吸收光谱法，测定了不同植物部位的硅富集情况。在干燥的植物部位，通过可变压力扫描电子显微镜的背散射模式可以很好地分辨出硅体。它们位于表皮下方的硅细胞和表皮附属物（刚毛、刺毛）中。硅体呈现出特定的形态、结构和组成，通过扫描电子显微镜结合X射线光谱、固态核磁共振、X射线衍射和拉曼光谱的联合分析得以阐明。其组成接近化学计量比的SiO₂（硅含量为41重量%，氧含量为56重量%），SiO₄/₂四面体优先排列成三维网络；较小比例呈链状和层状。具有整体无定形结构的硅体包含结晶沉淀物，这些沉淀物可以用α-石英进行索引。
