Why do leaves fall off?

Why do leaves fall when the weather is cold?

When you go to Qiu Lai in spring, nature will add new clothes, and the leaves will change from green clothes to Huang Chengcheng's golden clothes, and even put on bright red skirts to dance. So this is the function of using leaves as food? Photosynthesis. Photosynthesis is that plants absorb sunlight and skillfully convert carbon dioxide in the air and water absorbed from soil into nutrients. For photosynthesis, leaves produce chlorophyll and absorb sunlight.

In fact, there are many different pigments in leaves, except chlorophyll, lutein, carotene and so on. But leaves produce a lot of chlorophyll when they are photosynthetic. Because green is strong, it is green, so most of the leaves we see are green.

In winter, the temperature drops, the weather is dry, and some areas even freeze, so before entering winter, plants will temporarily stop photosynthesis and suck nutrients from leaves back into stems for storage. Because the leaves stopped photosynthesis and no longer produced chlorophyll, the original chlorophyll was slowly destroyed and disappeared because of the low temperature. Other pigments originally hidden in leaves, such as yellow, will appear. Some leaves turn red because they make red anthocyanins in autumn. No matter what color the leaves are, they will wither and fall in autumn because they lose the function of making nutrients.