A NOVEL ELECTRICAL METHOD TO STUDY PLASMODIAL CONTRACTIONS IN PHYSARUM - SYNCHRONY AND TEMPERATURE-DEPENDENCE

A novel electrical method for measuring the contraction rhythm occurri ng in Physarum polycephalum is described. The plasmodium is cultured i n a dish containing two electrically separated chambers, and when brid ging the two chambers the plasmodial veins of the Physarum complete an electrical circuit. The method is well suited for in situ measurement s of the overall contraction rhythm in Physarum over long time periods . The method has been used to investigate the temperature dependence o f the observed oscillations in the range from 1 to 30 degrees C. The p eriod exceeds 10 minutes at 1 degrees C. By using dishes with several separated chambers, the synchrony in a single plasmodium or the fusion between two specimens can be observed. A simple model calculation exp lains the salient features of the method and gives a good description of the results.