Ribosylzeatin and zeatin in tobacco crown gall tissue.

Cytokinins were extracted from two cultures of tobacco crown gall tumor tissue: an unorganized tissue and a teratoma which produced leafy shoots. On Sephadex LH-20 column chromatography, extracts of both types of tissue yielded two peaks of cytokinin activity with elution volumes similar to ribosylzeatin and zeatin. Ribosylzeatin and zeatin were detected and quantified by coupled gas chromatography - mass spectrometry selected ion monitoring (GC/MS SIM), comparable quantities being found in the two extracts. Full mass spectral evidence for the presence of ribosylzeatin in both tissues was obtained. No evidence was found for the presence of N(6)-(Δ(2)-isopentenyl)adenosine (i(6)Ade) or N(6)-(Δ(2)-isopentenyl)adenine (i(6)Ade) although these compounds have been reported to occur in cytokinin-habituated tobacco callus tissues.