十万个为什么·科学阅读30篇（5）
1 / 30
正在确认阅读权限…
Why Do Leaves Change Color in Fall?
秋天树叶为什么会变色？
-
In summer, leaves are green because of chlorophyll.夏天，叶子因叶绿素而呈绿色。
-
Chlorophyll helps plants make food from sunlight.叶绿素帮助植物利用阳光制造养分。
-
When days get shorter, trees stop making chlorophyll.白昼变短后，树木停止合成叶绿素。
-
Other colors like yellow and orange were always there.黄色和橙色等其他颜色原本就存在。
-
They were hidden by the strong green color before.此前被浓烈的绿色所掩盖。
-
Red colors form when sugar gets trapped in leaves.糖分在叶片中积聚时会形成红色。
-
Cold, sunny days help make bright red leaves.寒冷晴朗的天气有助于生成鲜红的叶子。
-
Finally, a thin layer cuts the leaf off the branch.最后，一层薄壁组织将叶片与枝条分离。