SOMATIC CHROMOSOMES IN TRADESCANTIA 
Lester W. Sharp 
Introduction 
In 191 3 the writer published the results of a study of chromosome 
behavior in the somatic cells of Vicia faba, the principal conclusion reached 
being that the splitting of the chromosomes is a phenomenon of the prophase. 
This view was directly opposed to that of Lundegardh (1910, 1912), Eraser 
and Snell (191 1), and Miss Digby (1910), who had contended that the 
telophasic alveolation of the chromosomes represents a splitting, and that 
the chromosomes remain through the ensuing resting stages as double 
structures. It was pointed out by the writer that this latter interpretation 
is rendered untenable by two lines of evidence which appear when the 
various transformations of the chromatin are minutely examined: first, 
the telophasic alveolation is very irregular and transforms each chromosome 
into an alveolar and then into a reticular structure which is in no true sense 
double, although chance arrangement of the vacuoles may often make it 
appear so; and second, the reticular chromosome, after separating from 
its fellows in the common reticulum during prophase, gives rise in a peculiar 
manner to a single (i.e., not double) slender thread in which vacuoles, all or 
nearly all of them new, appear and develop into the true split. 
The theory of telophasic splitting has been restated by Eraser (1914), 
Digby (1914, 1919), and Nothnagel (1916), who have employed it in the 
attempt to solve the problem of the heterotypic prophase. This point is 
one of fundamental importance, and will be taken up in some detail in 
the discussion. 
The present study of the somatic chromosomes of Tradescantia virginiana 
L. was undertaken not only to test the writer's position with respect to the 
time of chromosome splitting in somatic mitosis, but also, by determining 
more precisely the nature of the transformation of the chromosomes in the 
somatic telophase, to ascertain to what extent, if at all, this transformation 
will aid in the interpretation of the heterotypic prophase. Essentially the 
same methods were employed as in the former investigation of Vicia. 
Although the behavior of the chromatin in the two cases is strikingly 
similar, Tradescantia, so far as could be judged from the preparations 
obtained, proved to be inferior to Vicia for a study of the late prophases; 
for the analysis of the critical stages of the telophase and early prophase, 
however, it turned out to be quite superior, many exceptionally clear figures 
being obtained. Root tips alone were used. 
Among previous works dealing with Tradescantia may be mentioned 
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