The mechanism of ethylene and cyanide action in triggering the rise in respiration in potato tubers.

Ethylene and cyanide induce a sharp increase in respiration in potato tubers (Solanum tuberosum, var. Russet) attended by changes in the glycolytic intermediates which indicate that both gases enhance glycolysis. The level of sucrose also increases in response to both treatments. The data are taken to indicate that both cyanide and ethylene either activate or affect the link between the conventional electron transport chain and the cyanide-insensitive path. It is further proposed that this activation may well be the primary event leading to the rise in respiration. Ethylene increases the level of adenosine 5'-triphosphate and it is suggested that because of the 4- to 6-fold increase in the rate of electron flux through site I, which continues to operate in the over-all cyanide-insensitive path, the absolute levels of adenosine 5'-triphosphate will also be expected to increase in the presence of cyanide. The increase in sucrose content is considered to be the consequence of the rise in adenosine 5'-triphosphate concentration.