Cells undergoing endoreduplication duplicate their DNA without intervening mitosis, resulting in the gradual increase of their nuclear genome. Endoreduplication is widespread in eukaryotes, however most common in Angiosperms. Several biological processes such as cellular differentiation, cell expansion, metabolic activity and protection against DNA damage were linked to the endoreduplication process, altough biological evidence of a direct link is missing. Despite its common nature and apparent importance, both the physiological role and molecular control of endoreduplication are poorly understood. The ultimate goal of this project is to unravel the role of endoreduplication in the development and physiology of plants, and to indentify the molecular pathways that control the endoreduplication process.