Nucleic acid changes during cell expansion in the root

Abstract

In this investigation, the changes in the RNA and DNA complement of the cell have been studied during expansion and differentiation in the root. It has been shown that during expansion the RNA content per cell increases fourfold and the DNA content twofold. While the total RNA is increasing its base composition is changing. This, however, is related to changes in the relative proportions of two fractions the base composition of each of which remains constant. The base composition of the DNA does not change, but its susceptibility to acid treatment increases. It is suggested that the changing proportions of the two RNA fractions are due to a progressively partial enzymic degradation of the initial RNA complement, and these results may be of significance for the interpretation of the mechanism of cell growth in connexion with the changing catalytic pattern supported by the protein of the cell.