Experimental Studies on the Protoplasmic Streaming in the Myxomycete Plasmodium II

Abstract

The effects of various metabolic poisons and reduced oxygen tensions on the motive force of protoplasmic streaming in the plasmodium, Physarum polycephalum, were investigated by means of Kamiya's dynamoplasmometry. Following results has been obtained.1. No considerable changes in the motive force responsible for flow observed by removal of oxygen. Soon after the plasmodium was placed in fresh air, however, the motive force was slightly depressed for a while prior to its recovery.2. Similar results were also obtained in the case of CO-treatment. It was shown on the motive force-time curve (dynamoplasmogram) that the plasmodium shows negative taxis to CO.3. Pure O2 administered to both compartments of the chamber, inhibits the generation of the motive force to a certain extent.4. By the application of the relatively high concentrations of HCN, the magnitude of the motive force is increased considerably at first, but is soon followed by a decrease. Then, the protoplasm ceases to flow without coagulation.5. Plasmodium gains a tolerance for HCN in the case of the re-peated application of it.6. In 10-4M. NaN3, the motive force decreases slightly, but satisfactory recovery was obtained in this case.7. Other non volatile poisons were also investigated.