The number of K(+) channels in the plasma membrane of guard cell protoplasts changes in parallel with the surface area.
The activity of the two dominant K(+) channels in the plasma membrane of Vicia faba guard cell protoplasts was examined during pressure-driven swelling. For this purpose, the K(+) currents and the membrane capacitance (C(m)) of guard cell protoplasts were recorded in parallel. A rise in C(m), reflecting an increase of the membrane surface area, was coupled to a proportional rise in conductance of both the K(+) inward and K(+) outward rectifier. The activation kinetics of the K(+) channels were not affected during this process. The quantitative and temporal coupling of C(m) and K(+) conductance can hence be interpreted as the result of the addition of active inward and outward rectifier K(+) channels to the plasma membrane during an increase in surface area.
Homann
Ulrike
U
Institute of Botany, Technical University of Darmstadt, D-64287 Darmstadt, Germany. homann-u@bio.tu-darrmstadt.de
Thiel
Gerhard
G
D002462:Cell Membrane / Q000502:physiology* / Q000648:ultrastructure; D007887:Fabaceae / Q000502:physiology; D006874:Hydrostatic Pressure; D015640:Ion Channel Gating; D007700:Kinetics; D015221:Potassium Channels / Q000502:physiology*; D011523:Protoplasts / Q000502:physiology*; D013499:Surface Properties
D015221:Potassium Channels