, and vertically
in 48 h. A filament was fixed to the crown of the protuberance before any
arch was visible, but the basal half grew so quickly that on the second
morning the end of the filament was bowed greatly downwards. It was
therefore removed and fixed lower down. The line traced during these two
days extended in the same general direction, and was in parts nearly
straight, and in others plainly zigzag, thus giving some evidence of
circumnutation.
As the arched epicotyl, in whatever position it may be placed, bends
quickly upwards through apogeotropism, and as the two legs tend at a very
early age to separate from one another, as soon as they are relieved from
the pressure of the surrounding earth, it was difficult to ascertain
positively whether the epicotyl, whilst remaining arched, circumnutated.
Therefore some rather deeply buried beans were uncovered, and the two legs
of the arches were tied together, as had been done with the epicotyl of
Tropaeolum and the hypocotyl of the Cabbage. The movements of the tied
arches were traced in the usual manner on
[page 32]
two occasions during three days.
Pages:
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69