Stimulation of DNA synthesis and DNA polymerase activity by benzyladenine during early germination of maize axes

Abstract

Benzyladenine, a synthetic cytokinin, stimulates DNA synthesis during early germination of maize. A peak of stimulation is observed at 6 h in the period of 0–9 h of imbibition of embryo axes. Stimulation of DNA synthesis by the phytoregulator is dependent on RNA and (or) protein synthesis, since α-amanitin and cycloheximide inhibit such stimulation. Although DNA polymerase activity is stimulated by incubation of axes in the presence of benzyladenine, enzyme amount is apparently not increased. An enzyme located in the nuclei seems to be preferentially stimulated, and studies with specific inhibitors for polymerases and use of different templates suggest this enzyme could be of type γ. The nature of the mechanism of stimulation of DNA synthesis is discussed. Key words: benzyladenine, DNA synthesis, DNA polymerase, maize, germination.