很多时候，大家在进行Lecture4，一起来分析一下吧!
Now, this reabsorption process is very important for the tree and here is the key.
这个重新吸收过程对树很重要，关键来了。
It’s sensitive to light, meaning that too much exposure to sunlight can interfere with this process. So where does anthocyanin fit in here?
它对光很敏感，也就是说过多暴露在阳光下会干扰这个过程。那么花青素在这里扮演着什么角色呢?
Well, anthocyanin is more stable than chlorophyll. It’s not harmed as easily by the Sun or the cold.
花青素比叶绿素更稳定，不会轻易被太阳或寒冷损害。
So it’s still working long after the chlorophyll breaks down. But what does it do?
所以在叶绿素分解后很长时间它仍在工作。但是它做了什么呢?
The theory is that anthocyanin protects the reabsorption process from the sunlight.
理论是花青素保护这个重新吸收过程不被阳光损害。
For example, if you look closely at a red leaf on a tree, you’ll notice that most of the red pigment is on the upper side of the leave, the side facing the sun.
比如说，如果你近看一棵树上的一片红叶的话，你会发现大部分红色色素都在叶子向上的那面，也就是对着太阳的那面。
This new theory suggests that what the anthocyanin is doing there on top is shielding the rest of the leaf from the sunlight,
这种新理论认为，花青素在树叶朝上一面所做的就是挡住树叶其他部分的阳光，
and more importantly, allowing those important chemicals to be reabsorbed by the tree.
更重要的是，允许那些重要的化学物质被树木重新吸收。