Zellphysiologie, Elektrophysiologie der Zelle

A theoretical analysis of the voltage-current relationship is carried out in a membrane consisting of two fixed charge regions, of opposite sign, in contact. This is achieved by applying the diffusion equations to this system in conjunction with the Poisson-Boltzmann equation. The latter has been successfully applied by Mauro to determine the profiles of the electrostatic potential in his treatment of the capacitative property of such a system. It is shown that the system displays the property of rectification and is very similar in many respects to a solid state P-N junction diode. It is also shown that for the case of reverse bias, an electrical breakdown phenomena can occur. This is referred to as the "punch-through" effect. "Punch-through" was observed in experiments on the electrical characteristics of the membranes of Chara australis and Nitella sp. The experimental results are discussed in relation to the theoretical analysis.

By inserting microelectrodes into cells of various tissues, it was shown that elongated parenchyma cells in the phloem and protoxylem, which have larger membrane potential than inexcitable cells of other types, generate action potentials with conduction. The electrical features of these cells are essentially similar to those of nerve and muscle cells.