Kinetin incorporated into tobacco callus ribosomal RNA and transfer RNA preparations.

Kinetin, N(6)-furfuryladenine, was incorporated into tobacco (nicotiana tabacum L., var. Wis. No. 38) callus RNA isolated from rapidly growing tissue cultured in the presence of N(6)-furfuryladenine-8-(14)C or unlabeled kinetin. Approximately 0.7% of the radioactivity in the labeled kinetin added to the medium was recovered as N(6)-furfuryladenosine (fr(6)A) in the rRNA and tRNA preparations from the tobacco callus. The rRNA contained over 90% of these fr(6) A moieties. The extent of kinetin incorporation was four times greater than that observed for N(6)-benzyladenine. The radiochemical purity of the recovered fr(6) A was confirmed by three successive chromatographic purifications on Sephadex columns (LH-20 eluted with 35% ethanol, G-10 eluted with 20% ethanol, and LH-20 eluted with water). A cytokinin-active ribonucleoside with elution volumes corresponding to fr(6) A was isolated from the tobacco callus rRNA preparation. This compound was analyzed by gas-liquid chromatography and rigorously characterized as N(6)-furfuryladenosine by gas-liquid chromatography-mass spectrometry of the trimethylsilyl derivative.