Mobilization of respiratory metabolism in potato tubers by carbon dioxide.
Applying high concentrations of CO(2) to whole potato tubers stimulated a rapid and pronounced respiratory gas exchange, which persisted for a prolonged time. The upsurge in respiration was proportional to the applied CO(2) concentrations and was further augmented by high O(2) levels. Tests using whole potatoes, or potato tissue slices from tubers previously treated with CO(2), indicated that the rapid CO(2)-induced respiration is sensitive to cyanide during the first 24 hours of CO(2) application. The respiratory rise cannot be attributed to the emergence of a cyanide-resistant alternative electron transport pathway, although prolonged applications of CO(2), up to 72 hours, led to a gradual development of the pathway. CO(2)-stimulated respiration was accompanied by a pronounced decline in the content of starch and glucose 6-phosphate, suggesting an active utilization of respiratory substrates. The ATP content in the CO(2)-treated potatoes increased markedly, resembling similar increases in tissues undergoing respiratory upsurge.
Perez-Trejo
M S
MS
Department of Food Science, Rutgers University, New Brunswick, New Jersey 08903.