From anatomical segmentation to water flow simulation with CellSet and MECHA. A, Maize root cross section with exodermis after segmentation in CellSet. Successive cellular tissue types from the periphery are epidermis, exodermis, cortex, endodermis, pericycle, and other stele cells. Water potential boundary conditions were set at the epidermis surface and in xylem vessels (dark green). Bar = 100 µm. B, Simulated water fluxes in cell walls, in m s−1, combining impermeable apoplastic barriers with high kw, low KPD hydraulic properties, and 0.5 MPa water potential difference between the root surface and xylem, generating an average uptake flux at the root surface of 2 × 10−8 m s−1. Note that cell wall thickness is exaggerated to improve the visualization.