. The power of movement in plants . Plants; Botany. Ghap. XI. TBANSMITTED EFFECTS : VICIA. 52? Fig. 195. former trial; and after their tips (1-& mm. in length) hail been amputated, they were placed vertically in damp peat. Of these, three were not in the least affected and continued for days to grow straight downwards. Pour showed after 8 h. 30 m. a mere trace of curvature in the direction in which they had been acted on by geotropism; and in this respect they differed much from those which had been exposed for 1 h. 37 m., for many of the latter were plainly curved in 6 h. The curvature of
. The power of movement in plants . Plants; Botany. Ghap. XI. TBANSMITTED EFFECTS : VICIA. 52? Fig. 195. former trial; and after their tips (1-& mm. in length) hail been amputated, they were placed vertically in damp peat. Of these, three were not in the least affected and continued for days to grow straight downwards. Pour showed after 8 h. 30 m. a mere trace of curvature in the direction in which they had been acted on by geotropism; and in this respect they differed much from those which had been exposed for 1 h. 37 m., for many of the latter were plainly curved in 6 h. The curvature of one of these four radicles almost disappeared after 24 h. In the , the cur- vature increased during two days and then decreased. The third radicle became permanently bent, so that its terminal part made an angle of about 45° with its original vertical direction. The fourth radicle became horizontal. These two latter radicles oontintied during two more days to grow in the peat in the same directions, that is, at an angle of 45° be- neath the horizon and horizon- tally. By the fourth morning new tips had been re-formed, and now geotropism was able to act on them again, and they became bent perpendicularly downwards, exactly as in the case of the five radicles described in the last paragraph and as is shown in the figure (Fig. 195) here given. Lastly, five other radicles were similarly treated, but were ex- posed to geotropism during only 45 m. After 8 h. 80 m. only one was doubtfully affected; after 24 h. two were just per- ceptibly curved towards the side which had been acted on by geotropism; after 48 h. the one first mentioned had a radius of curvature of 60 mm. That this curvature was due to the action of geotropism during the horizontal position of the radicle, waa shown after 4 days, when a new tip had bten reformed, for it then grew perpendicularly downwards. We learn from thie. Vicia faba : radicle, rectangularly bent at A, after the amputation of the tip, due t
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Keywords: ., bookcentury1800, bookdecade, booksubjectbotany, booksubjectplants
