AbstractSignificant changes in nucleic acids are associated with both maturation and senescence ofHedera helixleaf tissues. DNA content was unaffected by senescence, and there were no quantitative differences between juvenile and transitional forms. The adult tissue, however, contained less DNA than the other forms. The total RNA content was reduced by senescence in juvenile and transitional tissue but not in adult. Maturation, on the other hand, progressively decreased the total RNA content. Similar changes in sRNA and rRNA indicate that maturation involves quantitative changes in these fractions. Quantitative differences in the nucleotide analyses suggest that different sRNA and rRNA species are responsible for the biological processes associated with maturation.