가을 단풍
가을이 되면 많은 나뭇잎의 색깔이 변한다. 왜 그럴까?
봄과 여름에 나뭇잎은 클로로필이라 불리는 녹색 물질을 생산한다. 클로로필은 햇빛, 물, 이산화탄소를 에너지로 변화시키며 나뭇잎을 녹색으로 만든다. 다른 색깔을 만들어내는 화학물질도 존재하지만 클로로필 때문에 막혀서 표출되지 못한다.
가을이 되면 나뭇잎이 클로로필을 점점 더 적게 생산하기 때문에 다른 색깔들이 보이게 되는 것이다.
Leaves on many trees change color in autumn. But why?
The falling leaves drift by the window
The autumn leaves of red and gold
I see your lips, the summer kisses
The sun-burned hands I used to hold
OK, more of Nat King Cole later. Here is how scientists explain why leaves change color in the fall.
In the spring and summer, leaves produce a green substance called chlorophyll. Chlorophyll changes sunlight, water and carbon dioxide in the air into food energy. Chlorophyll is also what makes leaves green.
Other chemicals in trees produce other colors. Carotenoids are orange, xanthophylls are yellow and anthocyanins are red.
Scientists say chlorophyll, carotenoids and xanthophylls are present in leaf cells all through the spring and summer. But the green chlorophyll blocks the yellow and orange colors.
In autumn, those colors can be seen because the leaves produce less and less chlorophyll, until the production stops.
Red leaves are the result of anthocyanin production in autumn. Yet scientists are not sure about the purpose of anthocyanins. Some believe they protect the leaves from too much of the sun’s radiation and protect cells from freezing during the cool autumn nights.
Others think anthocyanins may help leaves stay on a tree longer. They say the chemicals may make it possible for the tree to receive more growth chemicals from the leaves before the leaves fall off. The anthocyanins then stay inside the tree and its roots until they are needed again in the spring.
Leaves fall off many kinds of trees when the weather cools. The leaves slowly close the veins that carry the growth chemicals. And special cells form where the leaves attach to the branches of the tree. These cells cause the leaves to separate from the tissues that connected them to the tree.
The color of autumn leaves may not be the same each year. The colors are affected by the amount of rain that a tree receives. Lack of rain can delay the appearance of the colors.
Warm, wet weather in the autumn will reduce the brightness of the colors that do appear. And extremely cold weather will kill the leaves and cause them to drop early in the season.
Since you went away the days grow long
And soon Ill hear old winters song
But I miss you most of all my darling
When autumn leaves start to fall
봄과 여름에 나뭇잎은 클로로필이라 불리는 녹색 물질을 생산한다. 클로로필은 햇빛, 물, 이산화탄소를 에너지로 변화시키며 나뭇잎을 녹색으로 만든다. 다른 색깔을 만들어내는 화학물질도 존재하지만 클로로필 때문에 막혀서 표출되지 못한다.
가을이 되면 나뭇잎이 클로로필을 점점 더 적게 생산하기 때문에 다른 색깔들이 보이게 되는 것이다.
Leaves on many trees change color in autumn. But why?
The falling leaves drift by the window
The autumn leaves of red and gold
I see your lips, the summer kisses
The sun-burned hands I used to hold
OK, more of Nat King Cole later. Here is how scientists explain why leaves change color in the fall.
In the spring and summer, leaves produce a green substance called chlorophyll. Chlorophyll changes sunlight, water and carbon dioxide in the air into food energy. Chlorophyll is also what makes leaves green.
Other chemicals in trees produce other colors. Carotenoids are orange, xanthophylls are yellow and anthocyanins are red.
Scientists say chlorophyll, carotenoids and xanthophylls are present in leaf cells all through the spring and summer. But the green chlorophyll blocks the yellow and orange colors.
In autumn, those colors can be seen because the leaves produce less and less chlorophyll, until the production stops.
Red leaves are the result of anthocyanin production in autumn. Yet scientists are not sure about the purpose of anthocyanins. Some believe they protect the leaves from too much of the sun’s radiation and protect cells from freezing during the cool autumn nights.
Others think anthocyanins may help leaves stay on a tree longer. They say the chemicals may make it possible for the tree to receive more growth chemicals from the leaves before the leaves fall off. The anthocyanins then stay inside the tree and its roots until they are needed again in the spring.
Leaves fall off many kinds of trees when the weather cools. The leaves slowly close the veins that carry the growth chemicals. And special cells form where the leaves attach to the branches of the tree. These cells cause the leaves to separate from the tissues that connected them to the tree.
The color of autumn leaves may not be the same each year. The colors are affected by the amount of rain that a tree receives. Lack of rain can delay the appearance of the colors.
Warm, wet weather in the autumn will reduce the brightness of the colors that do appear. And extremely cold weather will kill the leaves and cause them to drop early in the season.
Since you went away the days grow long
And soon Ill hear old winters song
But I miss you most of all my darling
When autumn leaves start to fall
