Cessation of cytoplasmic streaming of Chara internodes during action potential

Cytoplasmic streaming of the Chara internode stops temporarilyat the peak of the action potential. Use of the technique ofvacuolar perfusion established that the sudden cessation ofcytoplasmic streaming is caused mainly by a temporary disappearanceof its motive force. Recovery of the rate of cytoplasmic streamingoccurs in parallel with that of the motive force. The ‘viscosity’of the cytoplasm remains almost unchanged during the whole periodof excitation except at the peak of the action potential. (Received February 1, 1968; )