Auxin-induced growth of tuber tissue of Jerusalem artichoke VI. Biochemical changes in chromatin during aging and cell expansion

Possible mechanisms by which auxin and gibberellic acid stimulateRNA synthesis were examined, using slices excised from cold-storedtubers of Jerusalem artichoke. The ratio of DNA in nucleo non-histone to the total DNA in chromatinincreased during the aging process. On the other hand, cellexpansion did not involve this kind of change in chromosomalcomponents. Gibberellic acid and 2,4-D showed no significanteffects on the ratio of DNA in nucleo non-histone to the totalDNA in chromatin. Melting points of DNA and nucleohistone did not differ significantlyaccording to their sources, i.e. unaged, aged and growing tissues. (Received November 13, 1970; )