The biochemical basis for thermoregulation in heat-producing flowers.
Thermoregulation (homeothermy) in animals involves a complex mechanism involving thermal receptors throughout the body and integration in the hypothalamus that controls shivering and non-shivering thermogenesis. The flowers of some ancient families of seed plants show a similar degree of physiological thermoregulation, but by a different mechanism. Here, we show that respiratory control in homeothermic spadices of skunk cabbage (Symplocarpus renifolius) is achieved by rate-determining biochemical reactions in which the overall thermodynamic activation energy exhibits a negative value. Moreover, NADPH production, catalyzed by mitochondrial isocitrate dehydrogenase in a chemically endothermic reaction, plays a role in the pre-equilibrium reaction. We propose that a law of chemical equilibrium known as Le Châtelier's principle governs the homeothermic control in skunk cabbage.
United Graduate School of Agricultural Science, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan.
Yui
Y
Umekawa
School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia.
Roger S
RS
Seymour
United Graduate School of Agricultural Science, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan.|Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan.
Kikukatsu
K
Ito
D000465:Algorithms; D001833:Body Temperature Regulation; D019069:Cell Respiration; D035264:Flowers / Q000737:chemistry* / Q000502:physiology*; D006358:Hot Temperature; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological; D018521:Plant Physiological Phenomena