Invertase Activity and its Relation to Hexose Accumulation in Potato Tubers

Hexose accumulation was shown to occur in freshly harvestedmature potato tubers (Solanum tuberosum L.) both after storageat 10 ?C and when subsequently transferred to low temperature(3 ?C) storage. In general, changes in hexoses and sucrose werefound to be related to changes in acid invertase activity. Totalacid invertase activity (i.e. assayed after destroying the endogenousinvertase inhibitor present in the extracts) generally reflectedsugar changes more closely than did basal activity (i.e. assayedwith the inhibitor present). There was no evidence of a specificalkaline invertase. A comparison of the temperature responsesof cultivar Record with that of two SCRI² clones demonstrateddistinct genotypic variation in the extent of hexose accumulation.However, these differences were not always reflected by genotypicdifferences in total invertase activity. Key words: Invertase inhibitor, glucose, fructose, sucrose