Plants have evolved complex nanofibril-based cell walls to meet diverse biological and physical constraints. How strength and extensibility emerge from the nanoscale-to-mesoscale organization of growing cell walls has long been unresolved. We sought to clarify the mechanical roles of cellulose and matrix polysaccharides by developing a coarse-grained model based on polymer physics that recapitulates aspects of assembly and tensile mechanics of epidermal cell walls. Simple noncovalent binding interactions in the model generate bundled cellulose networks resembling that of primary cell walls and possessing stress-dependent elasticity, stiffening, and plasticity beyond a yield threshold. Plasticity originates from fibril-fibril sliding in aligned cellulose networks. This physical model provides quantitative insight into fundamental questions of plant mechanobiology and reveals design principles of biomaterials that combine stiffness with yielding and extensibility.

植物已经进化出复杂的基于纳米纤维的细胞壁，以满足不同的生物和物理限制。长期以来，一直没有解决如何从生长细胞壁的纳米级到中级组织中出现强度和可扩展性。我们试图通过开发基于聚合物物理的粗粒度模型来阐明纤维素和基质多糖的机械作用，该模型概括了表皮细胞壁的组装和拉伸力学方面。模型中简单的非共价结合相互作用会产生类似于原代细胞壁的成束纤维素网络，并具有超过屈服阈值的应力依赖性弹性、硬化和可塑性。可塑性源于原纤维-原纤维在排列的纤维素网络中的滑动。