Changes in Content and Composition of the Fructose Polymers in Tubers of Helianthus tuberosus L. during Growth of Daughter Plants

Most of the dry weight of sprouting Jerusalem artichoke tuberswas lost during the first few weeks of growth of the new shoots;at least 80 per cent. of this loss was accounted for by disappearanceof polymerized fructose. It was demonstrated that much, if notall, of this material was translocated to the growing shoots,presumably in the form of sucrose. Depolymerization of fructoseresidues occurred during this process, and individual changesin the mono-, oligo-, and poly-saccharide fractions were consistentwith the hypothesis that a specific hydrolytic enzyme, knownto occur in tuber extracts, is involved.     

The Metabolism of Fructose Polymers in Plants: II. EFFECT OF TEMPERATURE ON THE CARBOHYDRATE CHANGES AND MORPHOLOGY OF STORED TUBERS OF HELIANTHUS TUBEROSUS L.

It is confirmed that the change in optical rotation of extractsobtained from tubers during dormancy is correlated with theconversion of fructosan to oligosaccharides of lower molecularweight, and that there is an associated increase in the combinedglucose content. Storage at 2° C. both accelerated and greatlymagnified this process; storage at 20° C. considerably depressedit. The change is not initiated or controlled by the dormantbuds. Tubers kept at 20° C. throughout the dormancy periodsprouted to give daughter tubers; new plants did not develop,even after some months. Normal sprouting was induced by keepingthe dormant tubers at 2° C. for 7 weeks.