Effects of Cyanide and Ethylene on the Respiration of Cyanide-sensitive and Cyanide-resistant Plant Tissues

Abstract

The effects of cyanide and ethylene, respectively, were studied on the respiration of a fully cyanide-sensitive tissue, the fresh pea [Pisum sativum], a slightly cyanide-sensitive tissue, the germinating pea seedling, and a cyanide-insensitive tissue, the cherimoa [Annona cherimola] fruit. Cyanide inhibition of both fresh pea and pea seedling respiration was attended by a conventional Pasteur effect where fermentation was enhanced with an accumulation of lactate and ethanol and a change in the level of glycolytic intermediates indicative of the activation of phosphofructokinase and pyruvate kinase accompanied by a sharp decline in ATP level. In these tissues, ethylene had little or no effect on the respiration rate, or on the level of glycolytic intermediates or ATP. By contrast, ethylene and cyanide enhanced both respiration and aerobic glycolysis in cherimoya fruits with no build-up of lactate and ethanol and with an increase in the level of ATP. For ethylene to stimulate respiration the capacity of cyanide-resistant respiration must be present.