Abbreviations: C, capacitance; d, distance between the edges of the a pair of pulvinules; DPDT, double pole double throw switch; HEC, a hydroelastic curvature model; I, electrical current; L, the hydraulic coefficient of pore permeability; P, hydrostatic pressure; PXI, PCI eXtensions for Instrumentation; Q, charge of capacitor; t, time; U, voltage; ta, characteristic time of the pore opening; tr, characteristic time of fluid transfer.

monitor the opening of single subunits while single channel current is recorded. Fluorescence intensity changes of FRET pairs or environment-sensitive dyes allow us to distinguish the movement of the four subunits (Blunck et al., 2008). We successfully imaged the diffusion of single channels in the bilayer using an EMCCD camera and now seek to correlate their fluorescence intensity, which is associated to a partial or a full opening, with the occurrence of subconductance levels.