植物细胞壁中手性纤维素原纤维的组织：受限在圆柱边界内的液晶

中文摘要 AI 辅助

采用偏振光学显微镜识别木质部细胞壁中纤维素微纤丝的排列顺序。圆柱壳内的直线、螺旋、环、交叉螺旋和扭转螺旋组织是弹性变形与表面锚定平衡的平衡态。建立这五种组织的计算模型以模拟其双折射彩色轮廓。这五种织构呈现独特的光学特征，在巨桉（Eucalyptus grandis）的横切面中可清晰识别。用于支撑的韧型纤维细胞具有扭转螺旋状细胞壁；用于高速吸水的导管细胞由螺旋层及覆盖其上的涡旋阵列层构成；用于径向运输的射线细胞为交叉螺旋状。利用双折射颜色分布测量微纤丝角（MFA）与细胞壁半径的关系：在纤维细胞壁中，MFA分别与曲率、弯曲度及表面锚定显著相关；在导管细胞壁中，涡旋阵列包含手性序的焦点圆锥畴和向列序的拓扑缺陷，表明纤维素原纤维的相变导致图案形成。细胞壁中的液晶相和图案揭示了细胞壁增厚及细胞分化的机制，细长管中填充的长而刚性的扭转原纤维产生的 frustration 使树木形成螺旋通道网络，将脆性薄层转化为弹性、抗撕裂、自修复的组织。

英文摘要

The order of cellulose microfibrils in xylem cell walls is identified using polarized optical microscopy. The line, helix, ring, crossed helix, and twisted helix organizations in a cylindrical shell are the equilibrium states of balanced elastic deformation and surface anchoring. A computational model of the five organizations is established to simulate their birefringent-colored profiles. These five textures present unique optical textures, which are clearly recognized in the cross sections of Eucalyptus grandis. The libriform fiber cell for support has a twisted helical cell wall. The vessel cell for high-speed water uptake consists of a helical layer covered by a layer of vortex array. The ray cell for radial transportation is crossed helical. The microfibril angles versus the radius of the cell wall were measured utilizing the distribution of birefringence colors. In fiber cell walls, the MFA is significantly correlated with the curvature, bending, and surface anchoring, respectively. In vessel cell walls, the vortex array includes focal conic domains of chiral order and topological defects of nematic order, suggesting that the phase transition of cellulose fibrils leads to pattern formation. Liquid crystal phases and patterns in the cell walls reveal how the cell wall thickens and how cells differentiate. Out of the frustration of long, stiff, twisting fibrils packed in slender tubes, trees generate the helical channel networks, transforming the brittle lamina into an elastic, tear-resistant, self-healing tissue.

发表机构

• National Yang Ming Chiao Tung University（国立阳明交通大学）

机构由 AI 辅助整理，请以论文原文为准。