FIG. 6.
Weakly rectifying currents in turn 4 root cells are smaller than those in turn 2 root cells. Ai In a turn 4 lateral wall slice pre-incubated with 2 mM 1-octanol, neurobiotin labeling (red) revealed a single root cell possessing a process extending between the type 2a fibrocytes (fc2a) of the spiral prominence. Nuclei were stained with DAPI (blue). Scale bar = 20 µm. Aii The root cell displayed small weakly rectifying whole-cell currents in response to voltage steps (−124 mV to +36 mV, −64 mV holding potential). Aiii Current–voltage (I–V) relationship for traces shown in Aii. B Membrane capacitance (Cm) measurements for root cells from turn 2 (n = 9) and turn 4 (n = 6; P = 0.0004). C Current density (pA/pF) measurements for the cells in B (P < 0.0001). Inward current at −120 mV was measured from I–V relationships, and divided by membrane capacitance. DVz measurements for these cells (P = 0.0466).