CHROMOSOMAL VESICLES AND THE STRUCTURE OF THE RESTING NUCLEUS IN PHASEOLUS

Abstract

1. When the chromosomes of Phaseolus reach the poles of the spindle they come in contact with each other, all lying parallel to the long axis of the spindle. The individual chromosomes can be traced by the indentations on the surface of the chromatin mass. 2. Vacuolization of chromosomes begins in the end nearest the equator of the cell (the proximal end). 3. The distal ends of the chromosomes do not become alveolized, but join to form the chromatin nucleolus. There is no plasmasome present in the root-tip cells of Phaseolus. 4. The linin sheath of the chromosomes becomes visible in conjunction with the telophasic vacuolization and can be traced through the interphase and resting condition, thus showing that the chromosomes remain distinct from one mitosis to the next. 5. The chromosome is considered as a linin bag filled with chromatin. Therefore, in the interkinetic nucleus the chromosomes are contiguous and the chromatin of adjacent chromosomes is discrete. 6. The chromosomes arise in the prophase by the chromosomal vesicles losing the achromatic globules within them and contracting to form the apparently homogeneous metaphase chromosomes.