英语词汇“geotropism”造句的方法、技巧、例句及翻译-英语例句辞典

Then we studied geotropism by observing how our plant grew toward the ceiling, even after we tipped the plant on its side for a few days. Because of Mr. Terupt 2010-10-11T00:00:00Z

The relations between vegetable and animal geotropism have been more recently investigated by J. Loeb. Popular scientific lectures 2012-04-24T02:00:17.273Z

But their sensitiveness to geotropism lasts for only 2 or 3 days; and the terminal part alone, for a length of between .2 and .4 inch, is thus sensitive. The Power of Movement in Plants

Thus I am now observing something about geotropism, and I had no idea a few weeks ago that this would have been necessary. More Letters of Charles Darwin — Volume 2

It must also be granted that geotropism has a bearing on the problem, since all plants twine upwards, and cannot twine along a horizontal support. Darwin and Modern Science

Lastly, five other radicles were similarly treated, but were exposed to geotropism during only 45 m. The Power of Movement in Plants

L, side of bean which lay on the peat, whilst geotropism acted on the radicle. The Power of Movement in Plants

This resulted from the tip bending quickly downwards, as it had now become much declined, and had thus gained a position highly favourable for the action of geotropism. The Power of Movement in Plants

B, point of chief curvature after the regeneration of the tip, when geotropism again acted. The Power of Movement in Plants

Ten other radicles similarly placed were touched on the lower side; and this would tend to make them bend from the cauterised side; and therefore, as now placed, upwards, or in opposition to geotropism. The Power of Movement in Plants

Besides geotropism and apogeotropism, there is, according to Frank, an allied form of movement, * 'Manual of the Botany of the Northern United States,' 1856, p. The Power of Movement in Plants

After the tips had been regenerated, geotropism was able to act on them, so that they now became bowed vertically downwards. The Power of Movement in Plants

The course pursued was mainly governed, as in the last case, by geotropism, but the line traced during 12 hours and magnified as before was more strongly zigzag, again showing circumnutation. The Power of Movement in Plants

Concluding Remarks.—Abundant evidence has now been given, showing that with various plants the tip of the radicle is alone sensitive to geotropism; and that when thus excited, it causes the adjoining parts to bend. The Power of Movement in Plants

Vicia faba: radicle, rectangularly bent at A, after the amputation of the tip, due to the previous influence of geotropism. The Power of Movement in Plants

They showed no signs of geotropism after an interval of 9 h., and were then thrown away. The Power of Movement in Plants

Whilst a root is penetrating the ground, the tip must travel first; and we can see the advantage of its being sensitive to geotropism, as it has to determine the course of the whole root. The Power of Movement in Plants

In the case previously described the basal part of the very short radicle from being turned vertically upwards, was at first very little affected by geotropism. The Power of Movement in Plants

After 24 h. several of the amputated radicles remained horizontal, but some showed a trace of geotropism, and one was plainly geotropic, for it was inclined at 40o beneath the horizon. The Power of Movement in Plants

Of the four horizontal radicles, one alone showed a trace of geotropism; of the three up-curved radicles, one retained this curvature, and the other two had become horizontal. The Power of Movement in Plants

But after three or four days when new vegetative points were formed, the radicles were again acted on by geotropism, and now they curved themselves perpendicularly downwards. The Power of Movement in Plants

Gossypium herbaceum.—The radicles of this plant bend, through the action of geotropism, for a length of about 6 mm. The Power of Movement in Plants

Many organs bend downwards through epinasty or apheliotropism or from their own weight; but we have met with very few cases of a downward movement in sub-aërial organs due to geotropism. The Power of Movement in Plants

But it appears at first sight immaterial whether this were effected by the whole growing part being sensitive to geotropism, or by an influence transmitted exclusively from the tip. The Power of Movement in Plants

These two kinds of sensitiveness conquer for a time the sensitiveness to geotropism, which, however, ultimately prevails. The Power of Movement in Plants

The capsules and flower-heads of some plants are bowed downwards through geotropism, and they then bury themselves in the earth for the protection and slow maturation of the seeds. The Power of Movement in Plants

Natural selection in connection with geotropism, heliotropism, etc., The Power of Movement in Plants

We therefore at first attributed the movement to geotropism; but a pot which had lain horizontally with the pods * 'The Movements and Habits of Climbing Plants,' 1875, p. The Power of Movement in Plants

Nevertheless, we fully admit that the weight of the part, as well as geotropism, etc., sometimes come into play. The Power of Movement in Plants

In both sets of cases the movement may be modified in a closely analogous manner by geotropism and by heliotropism; though few climbing plants are heliotropic. The Power of Movement in Plants

So that in these latter six cases the action of geotropism was much delayed. The Power of Movement in Plants

With the pea, therefore, the irritation from an attached object, and from geotropism when acting at right angles to the radicle, are nearly balanced forces. The Power of Movement in Plants

It was ascertained in several cases that this sensitiveness resides in the tip, which transmits an influence causing the adjoining upper part to bend in opposition to geotropism towards the moist object. The Power of Movement in Plants

After a time geotropism always prevailed, but its action was often delayed; and in three instances there was a most curious struggle between geotropism and the irritation caused by the cards. The Power of Movement in Plants

In these three last cases geotropism and the irritation caused by the attached squares alternately prevailed in a highly remarkable manner; geotropism being ultimately victorious. The Power of Movement in Plants

With radicles of the bean, when extended horizontally in damp air, geotropism always conquered the effects of the irritation caused by squares of card attached to the lower sides of their tips. The Power of Movement in Plants

Pisum sativum: a radicle extended horizontally in damp air with a little square of card affixed to the lower side of its tip, causing it to bend upwards in opposition to geotropism. The Power of Movement in Plants

Whether this can be of any service to them is very doubtful, but with seeds germinating on the surface it will slightly aid geotropism in directing the radicles to the ground.* The Power of Movement in Plants

Four others were not acted on by geotropism within the first 6 or 8 h., but after 23 h. were much bowed down. The Power of Movement in Plants

Therefore the cards, affixed to the lower sides of their tips, seemed to produce no effect; and geotropism easily conquered the effects of the irritation thus caused. The Power of Movement in Plants

As with the bean, the terminal growing part, after bending, sometimes straightened itself through the action of geotropism, although the object still remained attached to the tip. The Power of Movement in Plants

In these latter cases the irritation from the squares had over-powered geotropism; whilst in the former cases, in which the radicles were extended horizontally, geotropism had overpowered the irritation. The Power of Movement in Plants

As this latter movement occurred in complete darkness, and with peduncles arising from upright and from dependent branches, it cannot be due to apheliotropism or to epinasty, but must be attributed to geotropism. The Power of Movement in Plants

During neither of these days did the stolon bend downwards through geotropism or its own weight. The Power of Movement in Plants

The tertiary radicles, or those emitted by the secondary ones, are not influenced, at least in the case of the bean, by geotropism; so they grow out freely in all directions. The Power of Movement in Plants

This downward bending coincides with that due to geotropism, and both will cause the root to resume its original course. The Power of Movement in Plants

Uncauterised specimens similarly placed became much bent downwards through geotropism in the course of 5 or 6 hours. The Power of Movement in Plants

That this curvature was due to the action of geotropism during the horizontal position of the radicle, was shown after 4 days, when a new tip had been re-formed, for it then grew perpendicularly downwards. The Power of Movement in Plants

May 18th to 7.45 A.M. on 19th. acted on within this time by geotropism;* nor had its own weight caused it to bend downwards. The Power of Movement in Plants

Then geotropism prevailed and caused the apex to grow perpendicularly downwards. The Power of Movement in Plants

In whatever direction the primary radicle first protrudes from the seed, geotropism guides it perpendicularly downwards; and the capacity to be acted on by the attraction of gravity resides in the tip. The Power of Movement in Plants

But Sachs has proved* that the secondary radicles, or those emitted by the primary one, are acted on by geotropism in such a manner that they tend to bend only obliquely downwards. The Power of Movement in Plants

We next tried whether a shorter exposure to geotropism would suffice to produce an after-effect. The Power of Movement in Plants

As geotropism will obviously tend to check this curvature, seven seeds were allowed to germinate with proper precautions for their growth in a klinostat,* by which means geotropism was eliminated. The Power of Movement in Plants

单词	geotropism
例句	geotropism Then we studied geotropism by observing how our plant grew toward the ceiling, even after we tipped the plant on its side for a few days. Because of Mr. Terupt 2010-10-11T00:00:00Z The relations between vegetable and animal geotropism have been more recently investigated by J. Loeb. Popular scientific lectures 2012-04-24T02:00:17.273Z But their sensitiveness to geotropism lasts for only 2 or 3 days; and the terminal part alone, for a length of between .2 and .4 inch, is thus sensitive. The Power of Movement in Plants Thus I am now observing something about geotropism, and I had no idea a few weeks ago that this would have been necessary. More Letters of Charles Darwin — Volume 2 It must also be granted that geotropism has a bearing on the problem, since all plants twine upwards, and cannot twine along a horizontal support. Darwin and Modern Science Lastly, five other radicles were similarly treated, but were exposed to geotropism during only 45 m. The Power of Movement in Plants L, side of bean which lay on the peat, whilst geotropism acted on the radicle. The Power of Movement in Plants This resulted from the tip bending quickly downwards, as it had now become much declined, and had thus gained a position highly favourable for the action of geotropism. The Power of Movement in Plants B, point of chief curvature after the regeneration of the tip, when geotropism again acted. The Power of Movement in Plants Ten other radicles similarly placed were touched on the lower side; and this would tend to make them bend from the cauterised side; and therefore, as now placed, upwards, or in opposition to geotropism. The Power of Movement in Plants Besides geotropism and apogeotropism, there is, according to Frank, an allied form of movement, * 'Manual of the Botany of the Northern United States,' 1856, p. The Power of Movement in Plants After the tips had been regenerated, geotropism was able to act on them, so that they now became bowed vertically downwards. The Power of Movement in Plants The course pursued was mainly governed, as in the last case, by geotropism, but the line traced during 12 hours and magnified as before was more strongly zigzag, again showing circumnutation. The Power of Movement in Plants Concluding Remarks.—Abundant evidence has now been given, showing that with various plants the tip of the radicle is alone sensitive to geotropism; and that when thus excited, it causes the adjoining parts to bend. The Power of Movement in Plants Vicia faba: radicle, rectangularly bent at A, after the amputation of the tip, due to the previous influence of geotropism. The Power of Movement in Plants They showed no signs of geotropism after an interval of 9 h., and were then thrown away. The Power of Movement in Plants Whilst a root is penetrating the ground, the tip must travel first; and we can see the advantage of its being sensitive to geotropism, as it has to determine the course of the whole root. The Power of Movement in Plants In the case previously described the basal part of the very short radicle from being turned vertically upwards, was at first very little affected by geotropism. The Power of Movement in Plants After 24 h. several of the amputated radicles remained horizontal, but some showed a trace of geotropism, and one was plainly geotropic, for it was inclined at 40o beneath the horizon. The Power of Movement in Plants Of the four horizontal radicles, one alone showed a trace of geotropism; of the three up-curved radicles, one retained this curvature, and the other two had become horizontal. The Power of Movement in Plants But after three or four days when new vegetative points were formed, the radicles were again acted on by geotropism, and now they curved themselves perpendicularly downwards. The Power of Movement in Plants Gossypium herbaceum.—The radicles of this plant bend, through the action of geotropism, for a length of about 6 mm. The Power of Movement in Plants Many organs bend downwards through epinasty or apheliotropism or from their own weight; but we have met with very few cases of a downward movement in sub-aërial organs due to geotropism. The Power of Movement in Plants But it appears at first sight immaterial whether this were effected by the whole growing part being sensitive to geotropism, or by an influence transmitted exclusively from the tip. The Power of Movement in Plants These two kinds of sensitiveness conquer for a time the sensitiveness to geotropism, which, however, ultimately prevails. The Power of Movement in Plants The capsules and flower-heads of some plants are bowed downwards through geotropism, and they then bury themselves in the earth for the protection and slow maturation of the seeds. The Power of Movement in Plants Natural selection in connection with geotropism, heliotropism, etc., The Power of Movement in Plants We therefore at first attributed the movement to geotropism; but a pot which had lain horizontally with the pods * 'The Movements and Habits of Climbing Plants,' 1875, p. The Power of Movement in Plants Nevertheless, we fully admit that the weight of the part, as well as geotropism, etc., sometimes come into play. The Power of Movement in Plants In both sets of cases the movement may be modified in a closely analogous manner by geotropism and by heliotropism; though few climbing plants are heliotropic. The Power of Movement in Plants So that in these latter six cases the action of geotropism was much delayed. The Power of Movement in Plants With the pea, therefore, the irritation from an attached object, and from geotropism when acting at right angles to the radicle, are nearly balanced forces. The Power of Movement in Plants It was ascertained in several cases that this sensitiveness resides in the tip, which transmits an influence causing the adjoining upper part to bend in opposition to geotropism towards the moist object. The Power of Movement in Plants After a time geotropism always prevailed, but its action was often delayed; and in three instances there was a most curious struggle between geotropism and the irritation caused by the cards. The Power of Movement in Plants In these three last cases geotropism and the irritation caused by the attached squares alternately prevailed in a highly remarkable manner; geotropism being ultimately victorious. The Power of Movement in Plants With radicles of the bean, when extended horizontally in damp air, geotropism always conquered the effects of the irritation caused by squares of card attached to the lower sides of their tips. The Power of Movement in Plants Pisum sativum: a radicle extended horizontally in damp air with a little square of card affixed to the lower side of its tip, causing it to bend upwards in opposition to geotropism. The Power of Movement in Plants Whether this can be of any service to them is very doubtful, but with seeds germinating on the surface it will slightly aid geotropism in directing the radicles to the ground.* The Power of Movement in Plants Four others were not acted on by geotropism within the first 6 or 8 h., but after 23 h. were much bowed down. The Power of Movement in Plants Therefore the cards, affixed to the lower sides of their tips, seemed to produce no effect; and geotropism easily conquered the effects of the irritation thus caused. The Power of Movement in Plants As with the bean, the terminal growing part, after bending, sometimes straightened itself through the action of geotropism, although the object still remained attached to the tip. The Power of Movement in Plants In these latter cases the irritation from the squares had over-powered geotropism; whilst in the former cases, in which the radicles were extended horizontally, geotropism had overpowered the irritation. The Power of Movement in Plants As this latter movement occurred in complete darkness, and with peduncles arising from upright and from dependent branches, it cannot be due to apheliotropism or to epinasty, but must be attributed to geotropism. The Power of Movement in Plants During neither of these days did the stolon bend downwards through geotropism or its own weight. The Power of Movement in Plants The tertiary radicles, or those emitted by the secondary ones, are not influenced, at least in the case of the bean, by geotropism; so they grow out freely in all directions. The Power of Movement in Plants This downward bending coincides with that due to geotropism, and both will cause the root to resume its original course. The Power of Movement in Plants Uncauterised specimens similarly placed became much bent downwards through geotropism in the course of 5 or 6 hours. The Power of Movement in Plants That this curvature was due to the action of geotropism during the horizontal position of the radicle, was shown after 4 days, when a new tip had been re-formed, for it then grew perpendicularly downwards. The Power of Movement in Plants May 18th to 7.45 A.M. on 19th. acted on within this time by geotropism;* nor had its own weight caused it to bend downwards. The Power of Movement in Plants Then geotropism prevailed and caused the apex to grow perpendicularly downwards. The Power of Movement in Plants In whatever direction the primary radicle first protrudes from the seed, geotropism guides it perpendicularly downwards; and the capacity to be acted on by the attraction of gravity resides in the tip. The Power of Movement in Plants But Sachs has proved* that the secondary radicles, or those emitted by the primary one, are acted on by geotropism in such a manner that they tend to bend only obliquely downwards. The Power of Movement in Plants We next tried whether a shorter exposure to geotropism would suffice to produce an after-effect. The Power of Movement in Plants As geotropism will obviously tend to check this curvature, seven seeds were allowed to germinate with proper precautions for their growth in a klinostat,* by which means geotropism was eliminated. The Power of Movement in Plants
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