What are the mysteries of nature in autumn?

1, most plants will shed their leaves in autumn, and the leaves of plants will turn from green to yellow or red, which is related to the pigments contained in the leaves.

2. The temperature will drop gradually in autumn, generally slower than in winter. Due to the difference of dry and wet conditions, cold and rainy weather conditions or dry and cool weather conditions appear in different regions. In the cold late autumn, due to the large temperature difference between day and night, the water vapor transpiration during the day will condense at night, either dew or frost.

3. In autumn, the direct point of the sun gradually moves south from the northern hemisphere, passes through the equator after the autumnal equinox, and the sun directly shines in the southern hemisphere. Seen from the northern hemisphere, the angle of the sun gradually becomes lower, and the gap between day and night becomes smaller. At the autumnal equinox, the length of day and night is equal. In autumn, the distance between the earth and the sun is from far to near.

4. In autumn, most of late rice in South China is at jointing and booting stage, and cotton bolls crack and spit; Mid-season rice and summer corn entered the stage of grain filling maturity. In the east and west of South China, the task of drought and flood control is still very arduous. In South China after beginning of autumn, although the season is still midsummer, "beginning of autumn is full of yellow in ten days" and golden "autumn" is coming.

Extended data:

Most plants shed their leaves in autumn. This is an adaptation of plants to spend the cold season. In late autumn or early winter, due to the temperature drop, the root absorption is weakened, and the water supply for plants is difficult, which affects the photosynthesis and transpiration of plants. At this time, the leaves enter a state of aging.

On the one hand, the amount of auxin that inhibits leaf abscission is reduced, on the other hand, a large amount of abscisic acid that can make leaves abscission is formed. So in autumn, with the cold weather, the leaves of plants gradually fall off. Deciduous leaves are a good adaptive phenomenon for plants to keep water and survive the winter safely.