Metaphase of mitosis in root tip of mung bean showing persistent nucleoli (N) as visualized with light microscopy of aceto-carmine squash (upper left) and 0.5 μm plastic section (upper right), and transmission electron microscopy (main image). Despite what is described for mitosis in most introductory biology books, nucleoli or remnants thereof may persist throughout mitosis in a variety of organisms.

In addition to the nucleoli, the dense chromatin (C) is labeled at the metaphase plate. Line scales are 10 μm for LMGs and 1 μm for the TEMG.


Braselton, J. P. 1977. The nucleolus during mitosis in plants: Ultrastructure of persistent nucleoli in mung beans. In: Rost, T. L. and E. M. Gifford, Jr. (eds.). Mechanisms and Control of Cell Division, Dowden, Hutchinson and Ross, Inc. Pp. 194-211.

Vaughan, M. A. & J. P. Braselton. 1985. Nucleolar persistence in meristems of mung bean. Caryologia 38: 357-362.