| Abstract: | The response to light of a liverwort, Conocephalum conicum L., measured as a change in the resting potential, consists of two stages. The first stage is a slight depolarization dependent on light intensity. This plays the role of a generator potential (GP) which induces the second stage - an action potential of the all-or-none character. Action potentials induced by light and by electrical stimuli have the same properties, i.e. identical time course, propagation velocity, and refractory periods. A summation occurs of sub threshold light stimuli and of light and electrical stimuli. The presence of 5⋅10-−6 M DCMU cancelled the light response and blocked - by inhibition of the electron transport chain - the mechanism leading to GP generation. However, this effect did not produce any change in the response to electrical stimuli. |
