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第一段
1 .Listen to part of a lecture in a botany class.
听一段植物学课程上的演讲
第二段
1 .OK. Last time we talked about photosynthesis, the process by which plants use light to convert carbon dioxide and water into food.
好，上次我们讲了光合作用，植物利用光把二氧化碳和水转变为食物。
2 .Today I want to talk about another way light affects plants.
天我要讲光线影响植物的另一种方式。
3 .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.
我相信你们都在物理课上学过微观的光是如何运动的，并且我们只能看到某段波长的光。
4 .Plus, depending on the wavelengths, we see different colors.
而且波长不同，我们看到的颜色不同。
第三段
1 .Well, plants are also capable of distinguishing between different wavelengths of light.
植物也能辨别出光的不同波长。
2 .Now, I don't want to confuse you.
我不想把你们弄糊涂。
3 .It is not like plants have eyes.
这不是说植物有眼睛
4 .Plants don't see in the sense that humans or animals do, but they do have photoreceptors.
植物不像人类和动物一样能看见，但是它们有感光器。
第四段
1 .Photoreceptors are cells that respond to light by sending out a chemical signal.
感光器是通过发出化学信号来回应光照的细胞。
2 .And the organism, the plant, reacts to this signal.
然后，这株植物对该信号产生反应。
3 .In fact, the signals that plants get from their photoreceptors sometimes cause significant reactions.
事实上，植物从感光器感受到的信号有时会造成非常重大的反应。
第五段
1 .And many plants are seasonal.
而且很多植物都是季节性的。
2 .And one way they know when winter is ending and spring is beginning is by sensing the change in light.
它们感知冬天结束而春天来了的一个途径就是感知光的变化。
3 .The time when an adult plant flowers is based on the amount of light the plant senses.
一株成熟的植物什么时候开花是根据它感受到的光的数量决定的。
4 .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.
有些植物品种如果感受到太多的光就不会开花，而有些如果感到某一定量的光才开花
5 .Of course, these aren't conscious reactions.
当然，这些都不是有意识的反应。
6 .These plants just automatically respond to light in certain ways.
这些植物只是自动的对光有一些反应方式。
第六段
1 .Plants are also able to distinguish between specific wavelengths of light that the human eye cannot even see!
植物还可以分辨特定的人眼不能看到的波长。
2 .Specifically there's a wavelength called far-red.
特别是一种叫做远红的波长。
3 .Although why they call it far-red...
虽然叫做远红，
4 .I mean, it is not really red at all. It lies in the infrared range of the spectrum.
但我想说它并不是真正的红色。它位于光波谱的红外线区域。
5 .We can't see it, but plants can sense it as a different wavelength.
我们不能看到它，但是植物能够感受到这一波长。
第七段
1 .OK. Now I need to mention another thing about photosynthesis.
好，下面我需要讲关于光合作用的另一件事。
2 .I didn't explain how different wavelengths of light affect photosynthesis.
我还没解释不同的波长如何影响光合作用。
3 .When a plant absorbs light for performing photosynthesis, it only absorbs some wavelengths of light and reflects others.
当一株植物吸收光波来进行光合作用时，它只吸收某些波长并反射其他的。
4 .Plants absorb most of the red light that hits them, but plants only absorb some of the far-red light that hits them.
植物吸收大多数的红光，但它们只吸收一部分远红光。
5 .They reflect the rest.
它们把剩下的反射出去。
6 .Remember this, because it's going to be relevant in an experiment I want to discuss.
记住这个，因为他和下面讲的实验有关。
第八段
1 .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.
这个神奇的实验说明植物不仅能够察觉并回应某些波长的光线，它们还可以察觉和回应波长比例的变化。
第九段
1 .This experiment was called the Pampas experiment.
这个实验叫做Pampas实验。
2 .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.
个实验是关于植物回应用感光器得知的红光和远红光比例的变化。
3 .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.
一些生物学家猜想到一株植物在另一株的阴凉里就不会生长了，这是个由感受到异常的红光和远红光比例引起的反应。
第十段
1 .Imagine there are two plants.
好，想像两株植物，
2 .One below the other.
一株在另一株之下。
3 .The plant on top would absorb most of the red light for photosynthesis, but reflect most of the far-red light.
上面的植物因为光合作用会吸收大多的红光，但是反射出大多数远红光。
4 .That would lead to the plant in its shade sensing an unusual ratio.
这就导致它的阴影下的植物会感知到异常的比例。
5 .There will be less red light and more far-red light than normal.
与正常水平比，红光更少，远红光更多。
第十一段
1 .What that ratio signifies is important.
这个比例的含义很重要。
2 .A ratio of less red light to more far-red light would cause a reaction from the plant.
较少的红光，较多的远红光这种比例会引起植物的反应。
3 .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，因为它感受到没有足够的阳光来提供长大的能量。
第十二段
1 .To test their hypothesis, researchers took some electrical lights, um... actually, they were light-emitting diodes, or LEDs.
为了检验他们的假设，研究人员运用了电光源，嗯，其实是发光二极管，或LED。
2 .These light-emitting diodes could simulate red light.
这些发光二极管能够模拟红光。
3 .So they put these LEDs around some plants that were in the shade.
于是他们把LED放到阴影中的植物旁边。
4 .The LEDs produce light that the plants sensed as red.
LED发的光对植物来说是红光。
5 .But, unlike sunlight, the light from these LEDs did not support photosynthesis.
但是和阳光不同，LED的光不支持光合作用。
6 .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.
于是植物感受到了正常的红光与远红光比例，而且以继续长高作为回应，但其实这些植物并没有从光合作用中得到足够的能量来支持长高。
7 .And because they weren't getting enough energy to support their growth, most of the shaded plants died after a short time.
而且因为没有足够能量来长高，大多数阴影中的植物很快就死了。