The graph (left) displays parameters for the cytoplasmic pressure model that allow the contractile vacuole to dispense its entire volume in 1 s. The required pore diameter is plotted as a function of the choice of pore width, given a cytoplasmic pressure of 10 Pa (solid line), 100 Pa (dashed line), or 1,000 Pa (dotted line). Any reasonable choice of cytoplasmic pressure in between 10 and 1,000 Pa (blue shading) allows for a wide range of possible pore diameters and pore depths. The table (right) shows the allowable parameters for cytoplasmic pressure and vacuole and pore geometry. The width of the pore was estimated to be larger than the thickness of the membrane but smaller than the typical z-resolution for light microscopy. The pore diameter was derived such that the expulsion time = 1 s (see Methods S1).
