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托福TPO-28 Lecture 3(上)

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Listen to part of a lecture in a botany class.

听一段植物学课程。

OK. Last time we talked about photosynthesis, the process by which plants use light to convert carbon dioxide and water into food.

好了,上次我们讲了光合作用,即植物用光把二氧化碳和水转化成食物的过程。

Today I want to talk about another way light affects plants.

今天我想讲讲光影响植物的另一种方式。

I am sure you all know from physics class about how light moves in microscopic ways and that we can only see light when the wavelength of that light is in a specific range.

我相信你们从物理课上都知道了光是怎样做微观运动的,只有在光的波长达到一定范围时,我们才能看见光。

植物学.jpg

Plus, depending on the wavelengths, we see different colors.

还有,根据波长不同,我们看到的颜色也不同。

Well, plants are also capable of distinguishing between different wavelengths of light.

植物也能分辨出不同波长的光。

Now, I don't want to confuse you.

我不想把你们搞糊涂。

It is not like plants have eyes.

不是说植物有眼睛。

Plants don't see in the sense that humans or animals do, but they do have photoreceptors.

植物不像人或动物一样能看到光,但植物有光感受器。

Photoreceptors are cells that respond to light by sending out a chemical signal.

光感受器是一种细胞,遇光后会发出一种化学信号。

And the organism, the plant, reacts to this signal.

生物体,或说植物,会对信号产生反应。

In fact, the signals that plants get from their photoreceptors sometimes cause significant reactions.

事实上,光感受器发出的信号有时候会让植物产生剧烈反应。

And many plants are seasonal, and one way they know when winter is ending and spring is beginning is by sensing the change in light.

很多种植物是季节性的,它们感知冬去春始的一种方式就是感应光的变化。

The time when an adult plant flowers is based on the amount of light the plant senses.

成年植物开花的时间由植物感受到的光量而定。

Certain plant species won't flower if they sense too much light and some plants will only flower if they sense a specific amount of light.

一些植物在它们感受到过强的光时,是不会开花的,还有一些只会在感受到一定的光量时才会开花。

Of course, these aren't conscious reactions.

当然了,这些都不是有意识的反应。

These plants just automatically respond to light in certain ways.

这些植物遇光后自动以某些方式作出反应。

Plants are also able to distinguish between specific wavelengths of light that the human eye cannot even see!

植物还能分辨出一些特殊波长的光,这些光人眼是看不见的。

Specifically there's a wavelength called far-red.

特别是一种称为远红的波长。

Although why they call it far-red … I mean, it is not red at all.

为什么叫远红……我是说,这种光根本不是红色的。

It lies in the infrared range of the spectrum.

这种光在光谱上处于红外谱段。

We can't see it, but plants can sense it as a different wavelength.

我们看不见这种光,但植物能感受到这种不同的波长。

OK. Now I need to mention another thing about photosynthesis.

好了,现在我要提到光合作用的另一方面。

I didn't explain how different wavelengths of light affect photosynthesis.

我没有解释不同波长的光是怎么影响光合作用的。

When a plant absorbs light for performing photosynthesis, it only absorbs some wavelengths of light and reflects others.

植物吸收光进行光合作用时,它只吸收某些波长的光, 反射别的光。

Plants absorb most of the red light that hits them, but plants only absorb some of the far-red light that hits them.

植物吸收绝大多数接触到的红光,但只吸收部分接触到的远红光。

They reflect the rest.

其它光会被植物反射。

Remember this, because it's going to be relevant in an experiment I want to discuss.

记住这点,这和我将要讲的实验有关。

重点单词   查看全部解释    
certain ['sə:tn]

想一想再看

adj. 确定的,必然的,特定的
pron.

 
affect [ə'fekt]

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vt. 影响,作用,感动

联想记忆
spectrum ['spektrəm]

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n. 光谱,范围,系列

联想记忆
range [reindʒ]

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n. 范围,行列,射程,山脉,一系列
v. 排

 
microscopic ['maikrə'skɔpik]

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adj. 显微镜的,极小的,微观的

 
wavelength ['weiv.leŋθ]

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n. 波长,波段

联想记忆
specific [spi'sifik]

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adj. 特殊的,明确的,具有特效的
n. 特

联想记忆
organism ['ɔ:gənizəm]

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n. 生物体,有机体

 
relevant ['relivənt]

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adj. 相关的,切题的,中肯的

联想记忆
absorb [əb'sɔ:b]

想一想再看

vt. 吸纳,吸引 ... 的注意,吞并

联想记忆

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