Cell wall structure and formation of maturing fibres of moso bamboo (Phyllostachys pubescens) increase buckling resistance
Cell wall structure and formation of maturing fibres of moso bamboo (Phyllostachys pubescens) increase buckling resistance
复制标题
毛竹（Phyllostachys pubescens）的细胞壁结构和成熟纤维的形成增加了抗屈曲性
DOI：
10.1098/rsif.2011.0462
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发表时间：
2012-05-07
影响因子：
3.9
通讯作者：
Burgert, Ingo
中科院分区：
文献类型：
--
作者：
Wang, Xiaoqing;Ren, Haiqing;Burgert, Ingo
单子叶竹秆的机械稳定性主要归因于维管束的硬纤维帽适当地嵌入到柔软的薄壁组织基质中。由于缺乏维管形成层，竹子没有表现出阻碍几何适应机械负荷的次生加厚生长，并增加了在材料水平上进行结构优化的必要性。在这里，我们调查的精细结构和机械性能的纤维内成熟的毛竹，毛竹，具有较高的空间分辨率。纤维细胞壁被发现显示几乎轴向取向的纤维素原纤维，和刚度和硬度的细胞壁的中心部分保持基本一致的纤维在不同区域的纤维帽。纤维帽上的刚度梯度是由不同的细胞壁增厚产生的，细胞壁增厚影响组织密度，从而影响帽的不同区域中的轴向组织刚度。纤维壁中几乎轴向取向的纤维素原纤维使纤维的纵向弹性模量最大化，并且它们的木质化增加了横向刚度。这被解释为结构和机械优化，有助于高屈曲阻力的细长竹秆。
The mechanical stability of the culms of monocotyledonous bamboos is highly attributed to the proper embedding of the stiff fibre caps of the vascular bundles into the soft parenchymatous matrix. Owing to lack of a vascular cambium, bamboos show no secondary thickening growth that impedes geometrical adaptations to mechanical loads and increases the necessity of structural optimization at the material level. Here, we investigate the fine structure and mechanical properties of fibres within a maturing vascular bundle of moso bamboo, Phyllostachys pubescens, with a high spatial resolution. The fibre cell walls were found to show almost axially oriented cellulose fibrils, and the stiffness and hardness of the central part of the cell wall remained basically consistent for the fibres at different regions across the fibre cap. A stiffness gradient across the fibre cap is developed by differential cell wall thickening which affects tissue density and thereby axial tissue stiffness in the different regions of the cap. The almost axially oriented cellulose fibrils in the fibre walls maximize the longitudinal elastic modulus of the fibres and their lignification increases the transverse rigidity. This is interpreted as a structural and mechanical optimization that contributes to the high buckling resistance of the slender bamboo culms.