Mechanics of Parenchyma Tissue Based on Cell Orientation and Microstructure

The mechanics of parenchyma cells in fruit or vegetable tissue under external load is considered. The goal is to relate the micromechanical features of the individual cells to the macroscopic properties of the whole tissue. This article studies the effects of intercellular bonding and cell orientation on the stress-strain behavior of whole tissue. Beginning with general assumptions about cell shape and specific assumptions about cell-wall deformations, the equations of mechanical equilibrium in the cell wall and between cells are solved, subject to constraints on cell volume. Cell orientation relative to the direction of the applied load is predicted to have a significant effect on the likelihood of cell wall rupture, intercellular debonding, and intercellular slippage, and to have a minor effect on cell turgor pressure and the stress-strain relation of whole tissue. Predicted stress-strain behavior compared favorably with experimental data, suggesting that most of the important mechanical features have been incorporated into the analysis.