Cyclic Changes of Histones/DNA Ratio in Differentiating Nuclei of Metaxylem Cell Linein Allium Cepa Root Tip

Open Access
Publisher Website
Google Scholar
Abstract
Cytophotometric analysis of the nuclear DNA and histones content were carried out in procambial cells with develop into metaxylem in Allium cepa root tip. The collected data indicate that histones/DNA ratio is not constant. It is in fact highest during the endoreduplication process (stages 1 and 4), decreases in extrasynthesis of nucleolus associated DNA (stages 2 and 5) and reaches its lowest values during extra DNA release (stages 3 and 6). The results concerning stages 1, 2 and 3 are discussed in connection with the nuclear ultrastructure of the same stages.