Appearance and Disappearance of Cyanide-Resistant Respiration in Vigna mungo Cotyledons during and following Germination of the Axis.

Mitochondrial preparations isolated from black gram (Vigna mungo L.) cotyledons exhibited cyanide-resistant respiration which was of mitochondrial origin. The appearance and the disappearance of this alternative respiration took place during and following imbibition. During the first 6 hours of imbibition, the respiration was completely inhibited by cyanide, but after this time the alternative respiration markedly developed, reaching a maximal cyanide-resistance 12 to 16 hours after the start of imbibition. Subsequently, the alternative respiration gradually disappeared. The actions of cycloheximide and chloramphenicol indicated that the appearance was dependent on cytoplasmic protein synthesis and that the disappearance depended on both cytoplasmic and mitochondrial protein synthesis. The alternative pathway contributed to state 4 respiration, but not to state 3 respiration, in mitochondria from 1-day-old cotyledons. On day 3, it contributed to neither state 3 nor state 4.