BIDIRECTIONAL FLOW OF ENDOPLASM IN PHYSARUM-PLASMODIUM UNDER CENTRIFUGAL ACCELERATION

The behavior of cytoplasmic streaming in plasmodial strand of Physarum polycephalum was studied under centrifugal acceleration using a centr ifuge microscope of the stroboscopic type. Cytoplasmic streaming in th e plasmodium was greatly affected by changes in the acceleration. The endoplasmic flow in the centrifugal direction was accelerated, while t hat in the centripetal was retarded, by centrifugal acceleration. The centrifugal acceleration required to stop the endoplasmic flow in the centripetal direction did not cause total cessation of streaming but a lways induced a bidirectional flow of endoplasm in one and the same st rand. Each profile of velocity distribution of the bidirectional flow was both parabola with flattened apex. One possible cause of the bidir ectional flow is discussed.