Occurrence of Pseudonucleoli in Aneuploid Nuclei Induced by Colchicine in Plant Cells

The morphology of the nucleolar material in the nuclei of multinucleate cells or groups of cells produced in Allium cepa roots by treatment with colchicine was studied with the aid of silver impregnation as well as staining with basic fuchsin. From the 20th hours of recovery in about one third of the aneuploid nuclei which had not succeeded in organizing the nucleolus and which revealed the presence of prenucleolar bodies, other larger bodies were observed with the morphological characteristics of pseudonucleoli. These pseudonucleoli showed a clear segregation between the argyrophilic and the basophilic components of the nucleolus.