Interphase nuclear structure and heterochromatin in Phaseolus plant species.

Interphase nuclear structure was studied in five Phaseolus plant species. All the species showed chromocentric nuclear organization in both meristematic and differentiated cells. The number of chromocenters appeared to be a species-specific character. Percentage heterochromatin values, as determined by using three different staining techniques, were higher in meristematic cells than those in differentiated cells. There was a close correspondence between percentage heterochromatin and amount of highly repetitive DNA implying a possible involvement of the latter in chromatin condensation.