Figure 2.

Schematic longitudinal cross-sections of an (α, j) element, showing the three compartments (apoplast, cytoplasm, and vacuole) and the different ion fluxes included in the model. The cross-sections illustrate: (A) the symplastic (green), apoplastic (purple), and transmembrane (orange) ion fluxes; and (B) the membrane transport proteins (pumps, antiporters, symporters, and channels) present on the tonoplast and plasma membranes responsible for the transmembrane fluxes. For reaction processes see Figure S1.