AC Impedance Measurements on Chara corallina.I. Characterisation of the Static Cytoplasm

Abstract

Measurements of impedance (or admittance) of Chara corallina at frequencies of 1-10² Hz have revealed conduction, dielectric, geometrical and phenomenological properties of the plasmalemma and tonoplast.

At much higher frequencies, 10²-10⁴ Hz, the impedance of these membranes is mainly capacitative and small. Thus, measurements of the overall impedance of these frequencies largely reflect the electrical properties of regions in series with the membranes. The data and arguments presented indicate impedance measurements at these frequencies derive substantially from the static cytoplasm.

Results indicated the conductance of the static cytoplasm ranged from 0.5 to 300 S m^-2. Conductance was strongly dependent on temperature; a 10ºC rise in temperature produced more than a 2-fold increase in conductance.