COMPARISON OF THE EFFECTS OF SALICYLIC-ACID ON ALTERNATIVE PATHWAY IN SLICES OF DORMANT AND DORMANCY-BREAKING POTATO-TUBERS (SOLANUM-TUBEROSUM)

The effects of salicylic acid on the alternative pathway respiration in slices and isolated mitochondria of dormant and dormancy-breaking potato tubers was compared. The capacity of cyanide-resistant respiration rate (V-alt) in slices of dormant and dormancy-breaking potato tubers increased by 20-fold and 28-fold, respectively, during aging. However, the alternative pathway in both potato tuber slices was almost not engaged in the absence of KCN. Treatment with 20 mu M salicylic acid slightly increased the capacity of cyanide-resistant respiration rate in both dormant and dormancy-breaking potato slices, but only engagement dormancy-breaking potato slices was greatly enhanced. The effects of salicylic acid on the engagement of alternative pathways in slices of dormant potato tubers were not significant. The enhancing effect of salicylic acid in dormancy-breaking potato slices was also observed in isolated mitochondria. The elevated operation of the alternative pathway led to a decline of the RCR ratio and ADP/O values in isolated mitochondria. The reason for the differential effect of SA on the alternative pathway in dormant and dormancy-breaking potato slices was discussed.