Phosphate fluxes across the plant plasma membrane. Besides the Pi-uptake via the H/P transporter (B, black line, for clarity not shown in C), the plant loses Pi due to the ATP-release (light grey line). The difference between Pi-uptake and Pi-loss is the net Pi-balance of the plant (dark grey line). Without ATP-release (value 0 at the x-axis, black dots) the plant gains Pi. At a relative ATP-release and Pi-production of 1 (grey triangles) the plant release as much phosphate as it takes up, while at higher ATP-release values, the plant loses Pi. 