Cell Geometry and Junction Arrangement Define the Mechanical Robustness of Plant Tissues
Plant tissues are composed of immobile, pressurised cells that must maintain structural integrity under diverse environmental loads. Unlike animal tissues, which adapt through cellular rearrangement, plants must achieve mechanical robustness through the geometric configuration of their cellular networks. In this study, we establish a mechanistic link between cell geometry and mechanical resilience by integrating multilayer 3D mechanical simulations with cellular-resolution image analysis across a phylogenetically diverse panel of plant species, including Zea mays, Tradescantia zebrina, and Arabidopsis thaliana. We identify three-way junctions as fundamental mechanical elements that function as flexible hinges enabling mechanical strain accommodation in plant tissues. In contrast, four-way junctions are significantly stiffer and lack this strain-absorbing mechanism, providing a mechanical rationale for their biological avoidance. We also find that tissue material properties and strain response depend on edge lengths, cell layer, the degree of hexagonal shape, and turgor pressure response. These findings reveal the mechanism by which cell division patterns can actively tune tissue resilience to mechanical stress. This work provides new insights into the evolution of different cell shapes and offers clear principles for bio-inspired material science and tissue engineering.