Nucleic acid changes during cell expansion in the root

Abstract

In this investigation, the changes in theRNAandDNAcomplement of the cell have been studied during expansion and differentiation in the root. It has been shown that during expansion theRNAcontent per cell increases fourfold and theDNAcontent twofold. While the totalRNAis 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 theDNAdoes not change, but its susceptibility to acid treatment increases. It is suggested that the changing proportions of the twoRNAfractions are due to a progressively partial enzymic degradation of the initialRNAcomplement, 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.