The result was
that of the sixteen vertically embedded radicles, four continued for
several days to grow straight downwards, whilst twelve became more or less
bowed laterally. In two of the twelve, a trace of curvature was perceptible
in 3 h. 30 m., counting from the time when they had first been laid
horizontally; and all twelve were plainly bowed in 6 h., and still more
plainly in 9 h. In every one of them the curvature was directed towards the
side which had been downwards whilst the radicles remained horizontal. The
curvature extended for a length of from 5 to, in one instance, 8 mm.,
measured from the cut-off end. Of the twelve bowed radicles five became
permanently bent into a right angle; the other seven were at first much
less bent, and their curvature generally decreased after 24 h., but did not
wholly disappear. This decrease of curvature would naturally follow, if an
exposure of only 1 h. 37 m. to geotropism, served to modify the turgescence
of the cells, but not their subsequent growth to the full extent. The five
radicles which were rectangularly bent became fixed in this position, and
they continued to grow out horizontally in the peat for a length of about 1
inch during from 4 to 6 days.
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