Action Potentials in Lupinus angustifolius L. Shoots III. DETERMINATION OF THE REFRACTORY PERIODS

The refractory periods for action potentials (AP) were investigated in Lupinus shoots by application of pairs of electrical stimuli (d.c.). The response (AP) for the second stimulus is characterized. The second response differs in amplitude, range, and propagation velocity from the first, depending on the strength of the stimuli and the time interval between them. The absolute refractory period determined on this basis lasts 12 min, and the relative one from 12 to about 90 min. The character of the refractory phenomenon is similar in the case of nerves, only the processes in Lupinus are 103 to 105 times slower. The possibility of transmission of excitation from cell to cell is discussed.