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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.
這個精彩的實驗顯示，植物不僅能感受到某些特定波長的光并作出反應，還能感應到不同光之間波長比的變化。
This experiment was called the Pampas experiment.
這個實驗稱為潘帕斯實驗。
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.
實驗背后的思想是，植物的光感受器能感受到紅光與遠紅光的比率變化，且植物會對此作出反應。
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.
一些生物學家提出假設，如果一種植物被另一種植物（的影子）遮住了，前者會停止生長——這是由植物感受到的紅光與遠紅光的不尋常比率引起的反應。
OK . Imagine there are two plants. One below the other.
好了，想象有兩種植物，一種在另一種下面。
The plant on top would absorb most of the red light for photosynthesis, but reflect most of the far-red light.
在高處的植物會吸收絕大部分的紅光來進行光合作用，但反射絕大部分的遠紅光。
That would lead to the plant in its shade sensing an unusual ratio.
這會讓被影子遮擋住的植物感應到不尋常比率。
There will be less red light and more far-red light than normal.
紅光比正常情況少了，而遠紅光多了。
What that ratio signifies is important.
這個比率有重要意義。
A ratio of less red and to more far-red light would cause a reaction from the plant.
有更少的紅光與更多的遠紅光產生的比率會導致植物作出反應。
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.
植物會停止長高，因為植物能感覺到自己得不到足夠的陽光來為自己長大長壯供能。
To test their hypothesis, researchers took some electrical lights, um… actually, they were light-emitting diodes, or LEDs.
為了測試這個假說，研究人員用了一些電子燈，嗯……事實上他們用的是發光二極管，即LED燈。
These light-emitting diodes could simulate red light.
這些發光二極管能模擬紅光。
So they put these LEDs around some plants that were in the shade.
他們把這些LED燈放在被影子遮住的植物周圍。
The LEDs produce light that the plants sensed as red.
LED燈發出的光會被植物感知成紅光。
But, unlike sunlight, the light from these LEDs did not support photosynthesis.
但和陽光不同的是，這些LED燈發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.
那么這些植物感應到了紅光和遠紅光的合適比率并作出反應，繼續長高，但事實上植物并不能從光合作用中得到足夠的能量來維持這樣的生長。
And because they weren't getting enough energy to support their growth, most of the shaded plants died after a short time.
因為植物沒得到足夠的能量來維持生長，大多數被影子遮擋的植物很快就死了。
