SYNCHRONIZATION IN A PLASMODIAL STRAND OF PHYSARUM-POLYCEPHALUM AS A ONE-DIMENSIONALLY COUPLED OSCILLATOR SYSTEM

Transient behaviors in self-sustained oscillation of a plasmodial stra nd of Physarum polycephalum have been investigated for various externa l loads under isotonic conditions. Synchronization between divisions o f the strand has been observed in its formation process, which shows t hat the plasmodial strand can be considered as a one-dimensionally cou pled oscillator system. The synchronization has been found to proceed faster with increasing external load applied to the strand. It has fur thermore been found that the rate of increase of the amplitude of osci llation increases with the load, whereas the temporal behavior of its period is independent of the load. These results show that the oscilla tors themselves in the plasmodial strand do not depend on the external load, but the coupling between these oscillators is strongly affected with the external load. The experimental results have also been simul ated on the basis of one-dimensionally coupled van der Pol equations.