Endogenous cytokinins in vernalized winter wheat grains.

The soybean callus assay was used to study the effect of vernalization on the endogenous cytokinin levels of the grains of winter wheat (Triticum vulgare L.), cv. Ferto and Fema. Vernalization of the grains was carried out at 3° C in the dark for 0, 9, 18, 27, 36 and 45 days. Cytokinin activities could be detected in both the aqueous and butanol extracts of vernalized grains of both cultivars. It is suggested that flowering of winter wheat may involve changes in the levels of endogenous cytokinins during vernalization.