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According to the classic theory, this is true for the red pigment as well.
根據傳統理論，這對紅色也適用。
It was there in the leaf all along but it was hidden by the green chlorophyll.
它一直存在于樹葉中，但是被綠色的葉綠素藏起來了。
OK, so that’s the classic explanation and it’s partially right. Why do I say partially?
好了，這是傳統的解釋，部分是對的。為什么我說部分？
Well, it’s probably true for pigments like yellow or orange, but it doesn’t seem to hold for the red pigment.
因為這對像黃色和橘色這樣的色素可能是正確的，但是似乎不適用于紅色色素。
Let’s back up a bit. Just what produces this red color in leaves? It’s a red pigment called anthocyanin.
我們往回倒一點。什么產生了樹葉中的紅色呢？是一種叫做花青素的紅色色素。
Here is where the classic explanation doesn’t seem to apply to red.
這就是傳統解釋似乎不適用于紅色的地方。
What’s interesting is that during the summer there was very little if any anthocyanin in the leaves,
有趣的是在夏天，樹葉中幾乎沒有花青素，
but in the weeks before a tree is about to drop its leaves, the production of anthocyanins increases significantly.
但是一棵樹開始落葉前幾個周，花青素開始大量增加。
In other words, unlike those other pigments, anthocyanins are not just unmasked by the breakdown of chlorophyll in autumn;
換句話說，和其他的色素不同，花青素不是因為葉綠素在秋天分解而開始顯現，
they are actually created at this time.
它們實際上是那個時候才產生的。
So that raises a question, why would a tree produce more anthocyanin just before dropping its leaves?
那么這就提出了一個問題：一棵樹在落葉之前為什么要制造出更多的花青素？
Why does the tree spend so much of its resources doing this just before the leaves fall off?
為什么樹要在所有的樹葉掉落之前花那么多資源這么做？
On the surface, that doesn’t make sense.
從表面來看這一點都說不通。
