Scientists at the Iwate
University in Japan have shown that the skunk cabbage -- a species of
arum lily and whose Japanese name, Zazen-sou, means Zen meditation
plant -- can maintain its own internal temperature at about 20 degrees Celsius,
even on a freezing day (see Physics
News Graphics).
The plant occurs in East Asia and northeastern North America, where
its English name comes from its bad smell and from the fact that its
leaves are like those of cabbage. Unlike the case of mammals, which
maintain their body temperature by constant metabolism in cells all
over the body, heat in the skunk cabbage is produced chiefly in the
spadix, the plant’s central spike-like flowering stalk through
chemical reactions in the cells’ mitochondria.
According to one of
the authors of the new study, Takanori Ito (taka1@iwate-u.ac.jp),
only one other plant species, the Asian sacred lotus, is
homeothermic, that is, able to maintain its own body temperature at
a certain level. Most other plants do not produce heat in this way
because they seem to lack the thermogenic genes (the technical name
for which, in abbreviated form, is SfUCPb). Moreover, the
researchers, studying subtle oscillations in the plant’s internal
temperature, claim that the thermo-regulation process is chaotic and
that this represents the first evidence for deterministic chaos
among the higher plants.
The resultant trajectory in the abstract
phase space (where, typically, one plots the plant’s temperature at
one time versus the temperature at another time) is a strange
attractor, which the authors refer to as a Zazen attractor, a "Zen
meditation" attractor.
Ito and Ito,
Physical Review E, November 2005