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托福TPO-28 Lecture 3(下)

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This fascinating experiment showed that plants not only detect and react to specific wavelengths of light, plants can also detect and react to changes in the ratio of one wavelength to another.

这个精彩的实验显示,植物不仅能感受到某些特定波长的光并作出反应,还能感应到不同光之间波长比的变化。

This experiment was called the Pampas experiment.

这个实验称为潘帕斯实验。

The idea behind the Pampas experiment had to do with the response of plants to changes in the ratio of red light to far-red light that the plants sense with their photoreceptors.

实验背后的思想是,植物的光感受器能感受到红光与远红光的比率变化,且植物会对此作出反应。

Some biologists hypothesize that a plant will stop growing if it's in the shade of another plant, a reaction that's triggered when it senses an unusual ratio of red light to far-red light.

一些生物学家提出假设,如果一种植物被另一种植物(的影子)遮住了,前者会停止生长——这是由植物感受到的红光与远红光的不寻常比率引起的反应。

植物光合作用.jpg

OK . Imagine there are two plants. One below the other.

好了,想象有两种植物,一种在另一种下面。

The plant on top would absorb most of the red light for photosynthesis, but reflect most of the far-red light.

在高处的植物会吸收绝大部分的红光来进行光合作用,但反射绝大部分的远红光。

That would lead to the plant in its shade sensing an unusual ratio.

这会让被影子遮挡住的植物感应到不寻常比率。

There will be less red light and more far-red light than normal.

红光比正常情况少了,而远红光多了。

What that ratio signifies is important.

这个比率有重要意义。

A ratio of less red and to more far-red light would cause a reaction from the plant.

有更少的红光与更多的远红光产生的比率会导致植物作出反应。

It would stop growing taller, because that plant would sense that it wasn't going to get enough sunlight to provide the energy to grow large.

植物会停止长高,因为植物能感觉到自己得不到足够的阳光来为自己长大长壮供能。

To test their hypothesis, researchers took some electrical lights, um… actually, they were light-emitting diodes, or LEDs.

为了测试这个假说,研究人员用了一些电子灯,嗯……事实上他们用的是发光二极管,即LED灯。

These light-emitting diodes could simulate red light.

这些发光二极管能模拟红光。

So they put these LEDs around some plants that were in the shade.

他们把这些LED灯放在被影子遮住的植物周围。

The LEDs produce light that the plants sensed as red.

LED灯发出的光会被植物感知成红光。

But, unlike sunlight, the light from these LEDs did not support photosynthesis.

但和阳光不同的是,这些LED灯发出的光不能用作光合作用。

So the plants sensed the proper ratio of red light to far-red light and reacted by continuing to grow taller, while in reality these plants were not getting enough energy from photosynthesis to support all of that growth.

那么这些植物感应到了红光和远红光的合适比率并作出反应,继续长高,但事实上植物并不能从光合作用中得到足够的能量来维持这样的生长。

And because they weren't getting enough energy to support their growth, most of the shaded plants died after a short time.

因为植物没得到足够的能量来维持生长,大多数被影子遮挡的植物很快就死了。

重点单词   查看全部解释    
photosynthesis [.fəutəu'sinθəsis]

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n. 光合作用

 
produce [prə'dju:s]

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n. 产品,农作物
vt. 生产,提出,引起,

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specific [spi'sifik]

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adj. 特殊的,明确的,具有特效的
n. 特

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react [ri'ækt]

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vt. 作出反应
vi. 起反应,起作用,反攻

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unusual [ʌn'ju:ʒuəl]

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adj. 不平常的,异常的

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reflect [ri'flekt]

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v. 反映,反射,归咎

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shade [ʃeid]

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n. 阴影,遮蔽,遮光物,(色彩的)浓淡
vt

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hypothesis [hai'pɔθisis]

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n. 假设,猜测,前提

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fascinating ['fæsineitiŋ]

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adj. 迷人的

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wavelength ['weiv.leŋθ]

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n. 波长,波段

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