Kinin requiring tobacco and soybean tissues incubated on a medium containing N,6-benzyladenine-8-C(14) incorporated C(14) into several RNA components including adenylic and guanylic acids. About 15% of the label taken up by the tissues appeared in RNA while the remainder was distributed among several metabolites in the soluble, nonpolynucleotide fraction. Tissue grown on a kinin labeled in the side chain (N,6-benzyladenine-benzyl-C(14)) also incorporated a small, but nevertheless repeatable, amount of radioactivity into minor RNA components.Ultracentrifugation studies and methylated albumin chromatography indicated that the bulk of the label from benzyladenine-benzyl-C(14) is in soluble RNA. Approximately 50% of the C(14) in soluble RNA is in a component which has chromatographic properties like that of benzyladenine.It is suggested that the biological action of the kinins may hinge on their providing substituted bases in RNA in tissues which through differentiation no longer synthesize RNA-methylating enzymes. As an alternative it was hypothesized that a small amount of benzyladenine was incorporated into a m-RNA, acting there as a derepressing agent, perhaps by preventing its normal repressing function.