渥太华的秋日狂想曲

An astronaut aboard the International Space Station captured this view of peak fall foliage around Ottawa, Canada on Oct. 14, 2020. Sugar maple leaves turn orange-red, and hickories turn golden-bronze during autumn, regionally known as “the Fall Rhapsody.”

Fall color reaches its peak when air temperatures drop and shortened daylight triggers plants to slow and stop the production of chlorophyll—the molecule that plants use to synthesize food. When the green chlorophyll pigment fades, various yellow and red pigments become visible.

Image credit: NASA EUSO

2020年10月14日，国际空间站上的一名宇航员在加拿大渥太华附近拍摄到了这张秋天树叶的照片。秋天，糖枫叶变成橙红色，山核桃变成金青铜色，当地称为“秋日狂想曲”。

当气温下降、日照缩短时，植物会减缓或停止叶绿素（植物用来合成食物的分子）的生成，此时秋色达到顶峰。当绿色的叶绿素色素褪去时，各种黄色和红色的色素就会显现出来。

影像来源: NASA EUSO