Experimental Studies on the Protoplasmic Streaming in the Myxomycete Plasmodium II

Abstract

The effects of various metabolic poisons and reduced oxygen tension on protoplasmic streaming in Physarum polycephalum were investigated by means of Kamiya''s dynamoplasmometry. Removal of oxygen produces little change in the motive force.. After the plasmodium is returned to fresh air, the motive force is slightly depressed prior to recovery. Similar results were also obtained with CO-treat-ment. The plasmodium shows negative taxis to CO. Pure O2 administered to both compartments of the chamber partially inhibits the generation of the motive force. By the application of relatively high concentrations of HCN, the magnitude of the motive force is increased considerably at first, but is soon followed by a decrease. The protoplasm then ceases to flow without coagulation. Plasmodium became a tolerant to HCN upon repeated application. In 10-4 [image], NaN3, the motive force decreases slightly, but satisfactory recovery is obtained in this case. Other non-volatile poisons were also investigated.