Radiorestoration by 3 cytokinins contained in yeast RNAs and extracts, of scorzonera tumor tissues exposed to cobalt-60 gamma rays.

The 3 natural cytokinins contained both in the extracts and RNA of yeast and the tumor tissues cultivated in vitro, elicit radiorestorative properties from the crown-gall tissues of Scorsonera submitted to Co60 gamma-rays. However the cytokinins produce no stimulating effect whatsoever on the non irradiated tissues that are nontheless highly stimulated by yeast extract and their RNA.