Nucleic Acid Metabolism in the Developing Primary Leaf and Senescing Coleoptile of Germinating Oats

Abstract

AbstractNucleic acid metabolism in the coleoptile and primary leaf tissues of the germinating oat (Avena sativa L.) seedling was studied. The concentrations of the different species of nucleic acid present at various stages of development were determined and the amounts of each compared. All species of nucleic acid in the coleaptile increased as the tissue elongated; but, with the onset of senescence all species decreased, especially rRNA. Exposing dark grown coleoptiles to light did not modify their capacity to synthesize nucleic acids. In the rapidly developing leaf, all species of nucleic. acid increased throughout early germination. A general enhancement in the synthesis of all species of nucleic acids resulted when dark‐grown‐leaves were exposed to light. Furthermore, the tRNA/DNA ratio remained constant in both tissues during development, whereas the rRNA/DNA ratio changed.