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"The Power of Movement in Plants"


The same remarkable experiment was next tried, as in the case of the bean;
namely, little squares of exactly the same size of the card-like sanded
paper and of very thin paper (the thicknesses of which have been given
under Vicia faba) were attached with shellac on opposite sides (as
accurately as could be done) of the tips of 13 radicles, suspended in damp
air, at a temperature of 65o - 66o F. The result was striking, for 9 out of
these 13 radicles became plainly, and 1 very slightly, curved from the
thick paper towards the side bearing the thin paper. In two of these cases
the apex became completely hooked after two days; in four cases the
deflection from the perpendicular and from the side bearing the thick
paper, amounted in from two to four days to angles of 90o, 72o, 60o, and
49o, but in two other cases to only 18o and 15o. It should, however, be
stated that in the
[page 177]
case in which the deflection was 49o, the two squares had accidentally come
into contact on one side of the apex, and thus formed a lateral gable; and
the deflection was directed in part from this gable and in part from the
thick paper.


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