biologia plantarum

Biologia plantarum 45:205-211, 2002 | DOI: 10.1023/A:1015184320536

Effects of 6-Dimethylaminopurine, 2-Aminopurine, Olomoucine and Sodium Vanadate on DNA Endoreduplication in Primary Roots of Pisum Sativum

M. Rosiak¹, J.T. Polit¹, J. Maszewski¹

¹ Department of Cytophysiology, University of Łódź, Łódź, Poland

The effects of 2-aminopurine, olomoucine, 6-dimethylaminopurine (inhibitors of cyclin-dependent kinases; CDK), and sodium vanadate (a potent inhibitor of protein phosphatases) on DNA endoreduplication were investigated during elongation and differentiation of the primary roots in Pisum sativum. When compared with the untreated control plants, at least one additional round of DNA replication was evidenced to occur within most cells, the majority of which have attained 4C DNA level, and a considerably greater portion of cells represented the endopolyploid state with nuclear DNA content approximating the 8C value. It is concluded that cellular commitment to DNA endoreduplication may appear not only as a consequence of suppression imposed directly upon CDK activity, but also as an indirect output connected with the decreased activity of cdc25 protein phosphatase, an enzyme necessary to turn the switch on for appropriate conformation of the CDK/cyclin B complex. By calculating the absorption profiles of Feulgen-stained nuclei, specific phosphorylation-dependent changes in chromatin condensation of endopolyploid cells have been revealed. It is proposed that acquisition of a certain critical level of chromatin condensation constitutes a prerequisite for additional rounds of DNA synthesis in plants.

Keywords: cyclin-dependent kinases; pea; protein phosphatases

Subjects: cyclin-dependent kinases; cytokinins; DNA endoreduplication, primary roots; olomoucin, DNA endoreduplication; pea, DNA endoreduplication; Pisum sativum; proteins, phosphatases, DNA endoreduplication; root, DNA endoreduplication; sodium vanadate, protein phosphatase

Published: June 1, 2002  Show citation