The influence of z _X on the steady state of the PLEs, which are calculated from Eqs. 18, a–e . The steady state values of the variables are plotted as functions of the pump rate at different values of z_X = −3, −1, 0, 1, 1.5. Vertical dotted lines indicate p = p_min. On the top and bottom right panels (z_X = −1), the concentrations, voltage, and volume are plotted for κ = 0 see the dotted curves). Volumes are normalized by the minimum volume at z_X = 0.