EFFECT OF ARTIFICIAL ELECTRON RECEPTORS ON THE NONLINEARITY OF THE CURRENT-INDUCED VOLTAGE RESPONSE IN THE MEMBRANE OF THE GREEN-ALGA HYDRODICTYON-RETICULATUM

The non-linear character of the voltage response of the intracellular electrical potential of the alga Hydrodictyon reticulatum to current i njection was studied using a microelectrode technique. The phenomenon was strongly affected by the potassium ion concentration in the medium and by artificial electron acceptors (ferricyanide and the tetrathial fulvalene cation), by inhibitors of photosystem II and membrane H-ATPa se, by ethanol and by barium ions. Consideration of all the results su ggests that the membrane potential dependence of potassium channels as well as changes in the ion concentration gradients in unstirred layer s are responsible for the non-linear response phenomenon.