Electric Impedance of the Plasmodium of a Slime Mold, Physarum polycephalum

Abstract

The impedance of the plasmodium of Physarum polycephalum was measured by using an alternating current Wheatstone bridge. A substitution method was used, and the frequencies applied were 30, 100, 300, 1000, 3000, and 10000 cycles per second. The impedance at a certain frequency changed rhythmically with a period which was found to be equal to that of the rhythmical change of protoplasmic streaming. The "frequency impedance loci" obtained were essentially the same as those of other living systems reported by Cole, Curtis, and others. The frequency at the maximum reactance was 100-1000 cycles per second and the phase angle was 48 [plus or minus] 3[degree] The impedance had a polarization impedance, consisting of a series resistance and a series capacitative reactance as its components, both of which were power functions of frequency.