Abstract
The spadix of skunk cabbage, Symplocarpus foetidus, maintains an internal temperature of around 20 oC even when the ambient air temperature drops to freezing. In long-term measurements of the spadix temperatures, we found that distinct complex oscillations occur in time series of the spadix temperature. To clarify the relation between the observed temperature oscillation and the mechanism of thermoregulation, detailed analysis of changes in the spadix temperatures was performed using dynamical system theory. It was revealed that the oscillation showed chaotic behavior, and the number of factors that control such a complex oscillation were predicted to be two. Furthermore, it was shown that the oscillatory period of the spadix temperature was independent of the weight of the spadix. Based on these results, it was concluded that the thermoregulation of skunk cabbage could be modeled by an analogy to a damping oscillation without any parameters of the weight of the spadix.
