In Vivo Ubiquinone Reduction Levels during Thermogenesis in Araceae1

In vivo ubiquinone (UQ) reduction levels were measured during the development of the inflorescences of Arum maculatum and Amorphophallus krausei. Thermogenesis in A. maculatum spadices appeared not to be confined to a single developmental stage, but occurred during various stages. The UQ pool in both A. maculatum and A. krausei appendices was approximately 90% reduced during thermogenesis. Respiratory characteristics of isolated appendix mitochondria did not change in the period around thermogenesis. Apparently, synthesis of the required enzyme capacity is regulated via a coarse control upon which a fine control of metabolism that regulates the onset of thermogenesis is imposed.