causing granules of protoplasm either to be actually generated in the
previously limpid fluid or to coalesce and thus to become visible.
Supplementary Observations on the Process of Aggregation in the Roots
of Plants.
It will hereafter be seen that a weak solution of the carbonate of
ammonia induces aggregation in the cells of the roots of Drosera; and
this led me to make a few trials on the roots of other plants. I dug up
in the latter part of October the first weed which I met with, viz.
Euphorbia peplus, being care- [page 64] ful not to injure the roots;
these were washed and placed in a little solution of one part of
carbonate of ammonia to 146 of water. In less than one minute I saw a
cloud travelling from cell to cell up the roots, with wonderful
rapidity. After from 8 m. to 9 m. the fine granules, which caused this
cloudy appearance, became aggregated towards the extremities of the
roots into quadrangular masses of brown matter; and some of these soon
changed their forms and became spherical. Some of the cells, however,
remained unaffected. I repeated the experiment with another plant of
the same species, but before I could get the specimen into focus under
the microscope, clouds of granules and quadrangular masses of reddish
and brown matter were formed, and had run far up all the roots. A fresh
root was now left for 18 hrs. in a drachm of a solution of one part of
the carbonate to 437 of water, so that it received 1/8 of a grain, or
2.024 mg. When examined, the cells of all the roots throughout their
whole length contained aggregated masses of reddish and brown matter.
Before making these experiments, several roots were closely examined,
and not a trace of the cloudy appearance or of the granular masses
could be seen in any of them. Roots were also immersed for 35 m. in a
solution of one part of carbonate of potash to 218 of water; but this
salt produced no effect.
I may here add that thin slices of the stem of the Euphorbia were
placed in the same solution, and the cells which were green instantly
became cloudy, whilst others which were before colourless were clouded
with brown, owing to the formation of numerous granules of this tint. I
have also seen with various kinds of leaves, left for some time in a
solution of carbonate of ammonia, that the grains of chlorophyll ran
together and partially coalesced; and this seems to be a form of
aggregation.
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