Poisson Compression Theory as a Unified Mechanical Framework for Biological Morphogenesis: A Cross Kingdom Application to Plant Cell Wall Mechanics and Shape Formation

Plant morphogenesis has been described through multiple independent frameworks, including turgor‑driven expansion, cell wall mechanics, microfibril alignment, differential growth, buckling, and reaction–diffusion patterning. Although each model explains a subset of phenomena, no unified mechanical theory has been established to connect microscopic material behavior with macroscopic plant form. Poisson Compression Theory (PCT), originally developed to explain anisotropic fascial lamination in the human retroperitoneum, provides a generalizable physical sequence—material phase transition → multiaxial tension → Poisson compression → buckling → fiber alignment → macroscopic shape. Here, we extend PCT to plant tissues and show that plant cell walls behave as poroelastic solids undergoing pectin‑dependent material phase transitions, and that turgor‑generated multiaxial tension induces orthogonal compression, buckling, and directional alignment of cellulose microfibrils. These processes mirror anomalous Poisson compression and tension‑dependent ECM alignment in animal tissues. Applying PCT to plant morphogenesis reveals that leaf ruffling, petal curvature, root tip geometry, stem twisting, and venation patterning arise from the same mechanical causal chain observed in animal ECM. This cross‑kingdom correspondence suggests that biological shape formation—despite distinct biochemical architectures—emerges from shared physical principles. We propose PCT as a unified mechanical framework for biological morphogenesis, capable of integrating plant and animal shape formation within a single tension‑compression paradigm.