Not only the total amount of RNA in the plant material but also the component bases were determined. After removal of the acid-soluble phosphates, the lipoids and part of the coloring matter, the RNA was hydrolyzed to mononucleotides in alkaline solution and these were separated by cooumn chromatography. The chromatogrpahy was worked out to a routine method which can be carried out without costly apparatus and with small amounts of eluate. The optimal time of hydrolysis with 1 [image] KOH at 37[degree] C was found to be 22 hours. Under these conditions not only cytidyl monophosphate but also adenyl monophosphate and uridyl monophos -phate were partly decomposed. Because of this the necessary correction factors were determined.