The Cytokinins of Cichorium intybus L. Root: Identification and Changes During Vernalization

Abstract

Summary A procedure to extract the cytokinins of chicory root has been established. First, the material is immersed in 80 % methanol at 3 °C overnight without stirring to recuperate the nucleotides. Second, stirring in methanol allows the recovery of the other chemical forms of cytokinins. GLC analysis of purified extracts indicates that t zeatin, 2IP, their respective riboside and ri-botide, and t zeatin and t ribosyl-zeatin glucosides are present in chicory root. During root vernalization the amounts of these compounds were determined by densitometry. The bases and nucleosides greatly increased at the beginning of the acquisition of flowering ability and markedly decreased thereafter. The glucosides changed in the opposite direction. The nucleotides, barely detectable in the course of the first five weeks of cold treatment, gradually increased in the second half of vernalization. The intervention of cytokinins in the flowering process is discussed.