Recovery Process of Protoplasmic Streamingfrom Its Cessation in Nitella Internodal Cell

Recovery process of protoplasmic streaming in a Nitella internodal cell has been investigated at various temperatures. It has been found that the protoplasmic streaming, after its cessation by a current stimulus to the cell, begins to occur slowly and more quickly recovers to its original steady flow with larger velocity at higher temperatures. The steady velocity exponentially decreases with increasing inverse temperature, and the recovery time, which is defined as the time required for the protoplasmic streaming to recover to the half-value of its steady velocity, shortens with increasing temperature. It has been shown that the recovery process of protoplasmic streaming is expressed by a function of nondimensional velocity and time scaled by the steady value and the recovery time, respectively. These results have been elucidated on the basis of two motional equations describing the flow dynamics of the protoplasm.