232 DUPLICATION OF GENERATIVE NUCLEI BY MEANS OF 
After this preliminary investigation of the habit of the pollengrains 
it was decided to use for pollination: 
1°. the pollen of Yellow Hammer n. V. W.L. 
2°.  , , Yellow Hammer n. N. 
3°. 4, …, , Yellow Hammer abn. N. 
4°. 4, =~ Yellow Hammer abn. W. 
SS» Gertrude abn. N. (for selfing only). 
This choice was based on the following considerations: 
In the first place it was intended, to use for pollination, in sharp con- 
trast to the normal pollen (Yellow Hammer n. V. W. L. and n. N .), the 
most characteristically abnormal pollen of Yellow Hammer abn. W. 
In the second place, I did not wish to neglect the pollen of a more 
mixed nature (that of Yellow Hammer abn. N .) in pollinating, as this 
might possibly throw light on the question whether, when normal fer- 
tile and abnormal, also fertile, pollengrains were simultaneously pre- 
sent in about equal numbers, the generative nuclei of the former or of 
the latter category would fertilise best. 
As abnormal, fertile, pollengrains, I consider, for reasons to be explai- 
ned in Chapter V, both the large, starch-filled, globular pollengrains 
and the plurinuclear pollengrains. I also hope to state, presently, on 
which grounds I have reason to suppose, that the abnormal treatment 
of the plants did not influence the female gametes in a similar way as 
the male ones. 
c. The artificial germination of the pollengrains. 
Evidently, it was of great importance to determine the germinating 
power of the abnormal fertile pollengrains, especially in comparison 
with the normal fertile ones. 
Pollengrains of plants, last mentioned sub 1°—4°, were for this pur- 
pose cultivated in hanging drops in canesugar-solution. As far as ger- 
mination is concerned, the pollen of the forced inflorescences of Yellow 
Hammer abn.N.and abn.W. behaved exactly as that of the other of these 
categories. The pollen was examined at the end of 24 hours. The result 
was as follows: in a solution of 20 % of sugarcane a number of pollen- 
grains could be induced to germinate, the normal ones formed tubes of 
normal width, the tubes of the plurinuclear ones were wider. In their, 
frequently bladderlike, tubes the nuclei could not rarely be clearly seen. 
The length of the pollentubes was very different: 
in a solution of 15 % a large number of pollengrains of both kinds, 
Te oe bec ar 
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