STATISTICAL AND PHYSIOLOGICAL STUDIES ON THE INTERPHASIC GROWTH OF THE NUCLEUS

¹ Institute of Biology, University of Minas Geraes, Belo Horizonte, Brazil

The author analyzes present knowledge on the problem of "rhythmic growth" of the nucleus as it appears from the point of view of statistical caryometric research. This analysis is carried out especially with regard to the problem of the intermediate steps during reduplication of nuclear volume to about 1.5 times the initial size.

The nature of these steps is analyzed experimentally in three different fields: (1) Interphasic growth of spermatogonia, whose nuclear size is compared with a meiocyte with a known number of chromosomes. (2) Interphasic growth of the uterine cells under different physiological conditions. (3) Interphasic growth of the granulosa cells of the ovary, and the transformation into luteal cells.

The interphasic nature of rhythmic growth is considered also as a possible explanation for the intermediate step during reduplication of nuclear size that is called sesquiphase.