Translocation of Sugars in the Concord Grape.

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Abstract
On the basis of radiochemical analyses, it was concluded that sucrose was the only form of sugar rapidly translocated in the grape cane. The C-14 label was introduced by supplying Cl4O2 to a single leaf on the cane under conditions favorable for photosynthesis. Appreciable quantities of labeled-glucose and-fructose were also found in the stem, but these appeared to be hydrolytic products of the translocatory sucrose, as inferred from the fact that the ratio of glucose-C-14 to fructose-C-14 approximated unity. These results accord with the data reported in the literature showing the complete absence of glucose and fructose, and the predominance of sucrose, in the sieve tubes of a considerable number of species (based on chromatographic analyses of the sieve tube exudate from these species). The convergence in results obtained by these disparate approaches provides supplementary evidence that the translocation of sugars occurs primarily in the sieve tubes or sieve cells of the phloem tissue.