Autumn is here, the leaves will slowly change from green to yellow. This seems to have become the law of nature. Have you ever thought about why the leaves of autumn turn yellow? Let's talk below.

All the leaves contain green chlorophyll. Trees use chlorophyll to capture light energy and the help of other substances in the leaves to store chemicals such as sugar.

In addition to chlorophyll, many leaves also contain other pigments such as yellow, orange, and red. Although these pigments cannot be used like chlorophyll, some of them can pass the captured light to chlorophyll.

In spring and summer, the content of chlorophyll in the leaves is much richer than other pigments, so the leaves are green in chlorophyll, and the color of other pigments is not visible.

With the aging of the leaves, although all the pigments contained in the leaves will be decomposed, the decomposition speed of lutein is relatively slow, so the leaves gradually become yellow.

Chlorophyll also has a weak point, that is, it is easy to be destroyed. In the fall, the factors that have an impact on chlorophyll changed. The temperature is getting lower and lower, and the light is gradually insufficient, so chlorophyll decomposes quickly in the leaves.

The air in autumn became dry, and the water in the leaves evaporated in large quantities through the leaf surface.

As the weather becomes cold and the root system weakens, the water absorbed from the surface decreases, making a water supply shortage, and the water will no longer be transported to the leaves, so the leaves fall, leaving bare branches.

Because most of the leaves have fallen, this reduces the water consumption of trees and makes the trees safe and winter.

Some leaves also contain many anthocyanins. The temperature of autumn and winter decreases and the ability of the leaves to transport sugar and water has weakened.

The glucose in the trees is constantly cumulative, and the increase in soluble sugar makes the cells appear acidic. In acidic conditions, the flowers of the flowers will become red, so some leaves become red.

The yellowing of the leaves is also related to the breeding of plants. Due to the reproduction of plants, the nutrients of the plants were consumed, which eventually caused leaves to die. As long as the flowers and fruits of plants are removed, it can relieve or prevent the aging of the leaves.

However, this is not commonly applied to all plants, and some leaves begin to fall before flowering. The protein will be reduced during the aging process of the leaves.

At the same time, the content of genetic materials will also be reduced, and the ability to photosynthesis will be greatly reduced. During the aging process of the leaves, the chloroplast will be severely damaged, and the leaves will fall down.

However, the leaves are not all yellow, and the green leaves of the maple tree become red in autumn. Why are the leaves different?

It is because the leaves are in addition to the green chlorophyll, orange-yellow carotene, and yellow lutein, and a small number of plants also contain anthocyanins. When the anthocyanins encounter cell liquid, other colors will appear.

Will all trees fall in autumn? Pine trees and cypress trees are evergreen plants. Their leaves have a longer life than other trees. Pine needles can live for 3 to 5 years.

When the old leaves of the pine needle fall off, the new leaves will grow. After the new leaves grow, the old leaves fall off and fall off, so the trees remain green appearance.