Evidence for the Uptake of Sucrose Intact into Sugarcane Internodes

Application of [(14)C]fructosyl sucrose was used to determine whether sucrose cleavage was necessary for sucrose uptake by sugarcane (Saccharum spp.) internode tissue. Although approximately 25% of (14)C in the apoplast was present as fructose, indicating some sucrose cleavage, less than 15% of the label was randomized in the sucrose that remained in the tissue after a 30 minute osmoticum rinse. This is insufficient to support cleavage and resynthesis as the sole sucrose transport scheme. The lack of randomization of label between the glucose and fructose moieties of the sucrose molecule was taken as presumptive evidence that sucrose does not have to be cleaved prior to uptake by parenchyma cells in sugarcane internode tissue.