The Behavior of Kinoplasm and Nucleclus 
in the Division of the Pollen Mother 
Cells of Asclepias Cornuti. 
BY WILLIAM C. STEVENS. 
With Plate V. 
In studying the development of the flower of Asclepias cornuti I 
was struck with certain pronounced characteristics of the kinoplasm 
and nucleolus in the pollen mother cell which seem to me to throw 
some light on the functions of those structures. 
The functions of the nucleus as a whole have, to a certain extent, 
been made out with a fair degree of ‘certainty. There is no doubt 
that the nucleus is the bearer of the inheritable qualities. The 
processes of fecundation and physiological experiment make this 
certain.!' The nucleus also has important functions connected 
with processes which involve chemical changes, such as the for- 
mation of starch, the production of secretions? and possibly of 
proteids,* and the formation of plasma membrane and cell wall. 4 
Regarding the specific functions of the different structures of the 
nucleus it seems clear that one purpose of the nuclear membrane 
is to enclose the nuclear sap so that it may not be lost to the nuc- 
leus by diffusion, and to keep the nuclear framework and nucleolus 
from being dissociated and drawn out through the cell by the 
movements of the protoplasm or during the translocation of the 
nucleus. By the action of reagents the nuclear wail may be made 
to shrink away from the surrounding cytoplasm, thus showing that 
the former may have a selective action in the passage of substances 
to and from the nucleus. ° 
It is possible, also, that the nuclear membrane is concerned in 
10. und R. Hertwig, Die Zelle und die Gewebe. 
2 Haberlandt, Ueber die Beziehungen zwischen Function und Lage des Zellkernes 
beiden Pflanzen pp 116-122. 
3 Strasburger. Zellbi!dung und Zelltheilung, p. 373. 
4 Tangl, E., Zur Lehre von der Kontinuitaet des Protoplasmas im Pflanzengewebe. 
(Sitzungsbver. d. Kgl. Akad. d. Wiss. zu Wien. Mathem.—Naturwiss. Klasse. Bd. 90. 
Abt. L. 1885. p. 10.) Also Haberlandt. 1. c., and Klebs. Beitraege zur Physiologie der 
Pflanzenzelle. (Untersuch, aus dem botan. Institut in Tuebingen. Bd. 2, p. 489. 
5 Guignard, Nouvelles recherches sur le noyau cellulaire. (Ann. d. sc. nat. Botan. 
Ser. VI. I. 20: p. 310.) 
(77) KAN. UNIV. QUAR., VOL. VII. NO. 2, APRIL, 1898. SERIES A. 
