Penetration and Distribution of Dimethyl Sulfoxide-35S in Potato Tubers

Abstract

Whole and cut potato tubers were immersed in 25% DM35SO for different lengths of time and then sectioned and autoradiographed. Penetration of DMSO is restricted by the periderm, but takes place relatively rapidly through buds and cut surfaces When entering through cut surfaces, it is most rapidly distributed via the xylem while most of the absorbed DMSO is in the parenchyma adjacent to the cut. Eventually DM35SO becomes distributed throughout the entire tuber with the exception of the phloem, which remains unlabeled. Our results confirm that DMSO distribution follows an apoplastic route and that the phloem of potato tubers exists as an interconnected symplastic network in which DMSO and the presence of sugars are incompatible.