The Power of Movement in Plants |
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Common terms and phrases
apex apheliotropic apogeotropism basal bead bean became bend beneath the horizon blade bowed Brassica oleracea Cassia cause caustic cauterised circumnutating movement close cotyle course cumnutation curvature curved damp darkness deflected described dicotyledonous direction diurnal position ellipses epicotyl exposed figure following morning geotropism glass filament ground growing growth heliotropic horizontal glass hypocotyl hypogean illuminated inch in height inch in length inclined lateral light leaf leaves ledons Leguminosa magnified main petiole manner ment Mimosa pudica move nearly nocturnal nutation nyctitropic movements observed original scale Oxalis peduncle petiole Phalaris plumule position pulvinus radicles right angles rise rose Sachs seed seed-coats seedlings sensitive shellac shoot shown side sink sleep slightly species squares of card stem stolon stood straight summit temperature terminal leaflet tically tips traced Trifolium upper surfaces upright upwards vertical glass Vicia faba whilst window Würzburg young leaf young plant zigzag zigzag line
Popular passages
Page 479 - We must therefore conclude that when seedlings are freely exposed to a lateral light some influence is transmitted from the upper to the lower part, causing the latter to bend.
Page 3 - In the course of the present volume it will be shown that apparently every growing part of every plant is continually circumnutating, though often on a small scale. Even the stems of seedlings before they have broken through the ground, as well as their buried radicles, circumnutate as far as the pressure of the surrounding earth permits. In this universally present movement we have the basis or groundwork of the acquirement, according to the requirements of the plant, of the most diversified movements.
Page 576 - It is hardly an exaggeration to say that the tip of the radicle thus endowed, and having the power of directing the movements of the adjoining parts, acts like the brain of one of the lower animals...
Page 575 - Finally, it is impossible not to be struck with the resemblance between the foregoing movements of plants and many of the actions performed unconsciously by the lower animals. With plants an astonishingly small stimulus suffices ; and even with allied plants one may be highly sensitive to the slightest continued pressure, and another highly sensitive to a slight momentary touch. The habit of moving at certain periods is inherited both by plants and animals ; and several other points of similitude...
Page 562 - The flowerpeduncles are likewise continually circumnutating. If we could look beneath the ground, and our eyes had the power of a microscope, we should see the tip of each rootlet endeavoring to sweep small ellipses or circles as far as the pressure of the sur1 p.
Page 576 - We believe that there is no stru.-ture in plants more wonderful, as far as its functions are concerned, than the tip of the radicle. If the tip be lightly pressed or burnt or cut, it transmits an influence to the upper adjoining part, causing it to...
Page 199 - ... from or to the exciting cause. A radicle may be compared with a burrowing animal such as a mole, which wishes to penetrate perpendicularly down into the ground. By continually moving his head from side to side, or circumnutating, he will feel any stone or other obstacle, as well as any difference in the hardness of the soil, and he will turn from that side ; if the earth is damper on one than on the other side, he will turn thitherward as a better hunting-ground. Nevertheless, after each interruption,...
Page 576 - ... the adjoining part bends from the light ; but when excited by gravitation the same part bends towards the centre of gravity. In almost every case we can clearly perceive the final purpose or advantage of the several movements. Two, or perhaps more, of the exciting causes often act simultaneously on the tip, and one conquers the other, no doubt in accordance with its importance for the life of the plant.
Page 1 - The most widely prevalent movement is essentially of the same nature as that of the stem of a climbing plant, which bends successively to all points of the compass, so that the tip revolves. This movement has been called by Sachs " revolving nutation ; " but we have found it much more convenient to use the terms circumnutation and circumnutate. As we shall have to say much about this movement, it will be useful here briefly to describe its nature. If we observe a circumnutating stem, which happens...
Page 575 - But the most striking resemblance is the localisation of their sensitiveness, and the transmission of an influence from the excited part to another which consequently moves. Yet plants do not of course possess nerves or a central nervous system ; and we may infer that with animals such structures serve only for the more perfect transmission of impressions, and for the more complete intercommunication of the several parts.