That the secretion acts on the seeds was also shown by some of them
being killed, or by the seedlings being injured. Fourteen cabbage seeds
were left for three days on leaves and excited [page 387] much
secretion; they were then placed on damp sand under conditions known to
be favourable for germination. Three never germinated, and this was a
far larger proportion of deaths than occurred with seeds of the same
lot, which had not been subjected to the secretion, but were otherwise
treated in the same manner. Of the eleven seedlings raised, three had
the edges of their cotyledons slightly browned, as if scorched; and the
cotyledons of one grew into a curious indented shape. Two mustard seeds
germinated; but their cotyledons were marked with brown patches and
their radicles deformed. Of two radish seeds, neither germinated;
whereas of many seeds of the same lot not subjected to the secretion,
all, excepting one, germinated. Of the two Rumex seeds, one died and
the other germinated; but its radicle was brown and soon withered. Both
seeds of the Avena germinated, one grew well, the other had its radicle
brown and withered. Of six seeds of the Erica none germinated, and when
cut open after having been left for five months on damp sand, one alone
seemed alive. Twenty-two seeds of various kinds were found adhering to
the leaves of plants growing in a state of nature; and of these, though
kept for five months on damp sand, none germinated, some being then
evidently dead.
The Effects of Objects not containing Soluble Nitrogenous Matter.
(16) It has already been shown that bits of glass, placed on leaves,
excite little or no secretion. The small amount which lay beneath the
fragments was tested and found not acid. A bit of wood excited no
secretion; nor did the several kinds of seeds of which the coats are
not permeable to the secretion, and which, therefore, acted like
inorganic bodies. Cubes of fat, left for two days on a leaf, produced
no effect.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account