Lateral transport of energy along the coupling membranes of cyanobacteria [Phormidium uncinatum]

The light-induced electric potential changes brought about local illumination of trichomes of cyanobacteria Phormidium uncinatum have been studied by means of extracellular electrodes. Responses of several electrodes located at various distances from the illuminated area of the trichome were monitored simultaneously. They turned out to be similar in shape: a rapid increase to the maximum value was followed by a slow decay toward a nonzero residual level. The results offer strong evidence in favor of power transmission along the trichome. The computerized experimental data lend support to the notion of a unified system of coupling membranes acting as a passive cable for electrical propagation, the cable parameters being tau C = 440 sec cm-2 and gamma = 0.07 cm.