The tip
of the shoot projected obliquely .4 of an inch above the ground, but by the
close of our observations, which lasted 47 h., it had grown, chiefly
towards its base, to a height of .85 of an inch. The filament was fixed
transversely to the basal and almost upright half of the shoot, close
beneath the lowest scale-like appendage. The circumnutating course pursued
is shown in the accompanying figure (Fig. 42). The actual distance
traversed from side to side was about .04 of an inch.
Fig. 42. Corylus avellana: circumnutation of a young shoot emitted from the
epicotyl, the apex of which had been injured, traced on a horizontal glass,
from 9 A.M. Feb. 2nd to 8 A.M. 4th. Movement of bead magnified about 27
times.
Pinus pinaster (Coniferae).--A young hypocotyl, with the tips of the
cotyledons still enclosed within the seed-coats, was at first only .35 of
an inch in height; but the upper part grew so rapidly that at the end of
our observations it was .6 in height,
Fig. 43. Pinus pinaster: circumnutation of hypocotyl, with filament fixed
across its summit, traced on horizontal glass, from 10 A.
Pages:
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113