Kazama Makoto, Watanabe Hiroto, Hasekura Chikako, Wakabayashi Takumi, Ishigure Takaaki, Oaki Yuya, Imai Hiroaki
School of Integrated Design Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan.
Faculty of Agriculture, Tokyo University of Agriculture, Funako, Atsugi, 1737, 243-0034, Japan.
Sci Rep. 2025 Jul 1;15(1):21009. doi: 10.1038/s41598-025-06906-w.
Biosilicas that are produced in vascular plants (plant opal), such as Poaceae, have a variety of shapes and functions and are regarded as an excellent model for the architectural design of artificial amorphous materials. In this work, we studied the micro- and nanostructures and mechanical and optical functions of plant opals on the bamboo culm, which is available as an important natural material. The surface of the culm wall is totally covered with silicified epidermal cells containing silica wedges. The biogenic silicious architectures, such as silicified cell walls and wedges, are composed of nanoscale particles ~ 20-80 nm in diameter with cellulose nanofibrils. Silica wedges, which have a relatively low organic content and relatively high hardness and Young's modulus, are initially formed on cellulose nanofibrils in an organic frame as a scaffold within a few weeks after the emergence of a bamboo shoot. Several months after the formation of the wedges, the epidermal cell walls, which protect the culm surface, are lightly silicified with cellulose nanofibrils. According to a numerical simulation, the silica wedges would have an optical function delivering sunlight to chloroplasts located under the epidermal cells.
在维管植物（如禾本科植物）中产生的生物硅石（植物蛋白石）具有多种形状和功能，被视为人工无定形材料建筑设计的优秀模型。在这项工作中，我们研究了竹茎上植物蛋白石的微观和纳米结构以及机械和光学功能，竹茎是一种重要的天然材料。茎壁表面完全覆盖着含有硅楔的硅化表皮细胞。生物成因的硅质结构，如硅化细胞壁和硅楔，由直径约20 - 80纳米的纳米级颗粒与纤维素纳米纤维组成。硅楔的有机含量相对较低，硬度和杨氏模量相对较高，在竹笋出土后几周内，最初在有机框架内的纤维素纳米纤维上作为支架形成。硅楔形成几个月后，保护茎表面的表皮细胞壁会被纤维素纳米纤维轻度硅化。根据数值模拟，硅楔具有将阳光传递到位于表皮细胞下方叶绿体的光学功能。
