Figure 2.

K⁺ contents and analysis of K⁺ fluxes at the plasma membrane and tonoplast resolved over the diurnal Reference Cycle as described in Figure 1 (12 h light:12 h dark, indicated by bars above). Shown are cytosolic and vacuolar [K⁺] (A), the net K⁺ flux across the plasma membrane and tonoplast (B), the K⁺ flux through the K⁺-permeable transporters at the plasma membrane, comprising the two K⁺ channels and the H⁺-K⁺ symporter (C), and the K⁺ flux through the K⁺-permeable transporters at the tonoplast, comprising the TPK and FV channels (D). K⁺ flux through the TPC channel accounted for less than 1% of either of the other channel fluxes, and has therefore been omitted for purposes of clarity. Note that positive flux is defined as movement of the ionic species (not the charge) out of the cytosol, either across the plasma membrane or the tonoplast.