Jin Kexia, Ling Zhe, Jin Zhi, Ma Jianfeng, Yang Shumin, Liu Xinge, Jiang Zehui
Key Lab of Bamboo and Rattan Science & Technology, International Center for Bamboo and Rattan, Beijing 100102, China.
State Key Lab of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
Polymers (Basel). 2021 Dec 31;14(1):143. doi: 10.3390/polym14010143.
The mechanical performance of bamboo is highly dependent on its structural arrangement and the properties of biomacromolecules within the cell wall. The relationship between carbohydrates topochemistry and gradient micromechanics of multilayered fiber along the diametric direction was visualized by combined microscopic techniques. Along the radius of bamboo culms, the concentration of xylan within the fiber sheath increased, while that of cellulose and lignin decreased gradually. At cellular level, although the consecutive broad layer (Bl) of fiber revealed a relatively uniform cellulose orientation and concentration, the outer Bl with higher lignification level has higher elastic modulus (19.59-20.31 GPa) than that of the inner Bl close to the lumen area (17.07-19.99 GPa). Comparatively, the cell corner displayed the highest lignification level, while its hardness and modulus were lower than that of fiber Bl, indicating the cellulose skeleton is the prerequisite of cell wall mechanics. The obtained cytological information is helpful to understand the origin of the anisotropic mechanical properties of bamboo.
竹子的力学性能高度依赖于其结构排列以及细胞壁内生物大分子的特性。通过组合显微镜技术可视化了沿直径方向多层纤维的碳水化合物拓扑化学与梯度微力学之间的关系。沿着竹茎的半径方向，纤维鞘内木聚糖的浓度增加，而纤维素和木质素的浓度逐渐降低。在细胞水平上，尽管连续的纤维宽层（Bl）显示出相对均匀的纤维素取向和浓度，但木质化程度较高的外层Bl的弹性模量（19.59 - 20.31 GPa）高于靠近管腔区域的内层Bl（17.07 - 19.99 GPa）。相比之下，细胞角的木质化程度最高，但其硬度和模量低于纤维Bl，这表明纤维素骨架是细胞壁力学性能的前提条件。所获得的细胞学信息有助于理解竹子各向异性力学性能的起源。
