Isolation and identification of substances inducing formation of tracheary elements in cultured carrot-root slices

The roots of a carrot (Daucus carota L.) cultivar, Kuroda-gosun, contain active substances causing formation of tracheary elements in cultured root phloem slices. In the roots of another carrot cultivar, Hokkaidô-gosun, such substances could not be detected but when root-phloem slices of this cultivar were cultured in the light, active substances were produced in the tissue. From the behavior in thinlayer chromatography and data from gas chromatography and mass spectrometry, the major active substance isolated from the roots of Kuroda-gosun was identified as zeatin ribonucleoside. Hydrolysis with HCl and alkaline phosphatase of the active substance in the amphoteric fraction from root slices of Hokkaidô-gosun, cultured in the light, gave rise to zeatin and zeatin ribonucleoside, respectively, indicating that the active substance produced in this material in the light may be zeatin ribonucleotide.