Because the synthesis of chlorophyll needs strong light and high temperature, in autumn, with the decrease of temperature, the light becomes weak, the synthesis of chlorophyll is blocked, chlorophyll is unstable, and it is easy to decompose under the light, and the decomposed chlorophyll can not be supplemented. Therefore, the proportion of chlorophyll in leaves decreases, while lutein and carotene are relatively stable and are not easily affected by the outside world. Therefore, the leaves appear yellow with these pigments. Spread around from the root.

Autumn is one of the four seasons. In China, traditionally, "beginning of autumn" in the 24 solar terms is taken as the starting point of autumn. Entering autumn means that rainfall and humidity tend to decrease or decrease, and everything in nature begins to mature from lush.

Season: In China, "beginning of autumn" among the 24 solar terms is traditionally taken as the starting point of autumn. Entering autumn means that rainfall and humidity tend to decrease or decrease. In nature, the qi of Yin and Yang began to change, the yang gradually declined, the yin gradually emerged, the climate changed from hot to cold, and everything was born with cold and gradually declined. According to modern meteorology, the autumn in the north temperate zone is from August 23rd (summer) to165438+1October 22nd (light snow). Autumn in the south temperate zone is from February 19 (rain in the northern hemisphere) to May 2 1 (xiaoman in the northern hemisphere).

Astronomy: In autumn, the direct point of the sun gradually moves south from the northern hemisphere, crosses 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. Seen from the ecliptic plane, the sun is on the background of Leo, Virgo and Libra.

Other related: eat more acidic food in autumn diet, the climate in autumn is dry and the temperature difference is uncertain, so it is necessary to protect the liver function of the body. In diet, it is necessary to "increase acid" to enhance the function of the liver and resist the invasion of excessive lung qi. Traditional Chinese medicine believes that autumn is a transitional period between two seasons in Xia Dong, and the temperature changes from hot to cold, so health care should also change from "nourishing yang" to "nourishing yin". Avoid overeating. In autumn, most people tend to eat too much because of the pleasant climate and abundant food. Eating too many calories will turn into fat accumulation, which will make people fat. Autumn diet, we should pay attention to the right amount, can not indulge appetite, eat and drink. Avoid spicy and cold food. Avoid eating greasy and fried food. Avoid eating dry food. Avoid eating aquatic plants.

Health: Autumn is the best time for health, so eat more vegetables. Vegetables can not only preserve health, but also help treat some diseases. So, which vegetables are healthy in this season? In dry autumn, you should eat more green leafy vegetables, because it has high vitamin content, so it is good to eat more. Dark vegetables such as spinach, green vegetables, celery, chrysanthemum, amaranth, carrots, etc. Like brown-red vegetables, they are rich in vitamins and carotene.

You can eat lotus roots in autumn. Lotus root is the king of oriental vegetables. Rich in polyphenols, it can improve immunity and resist aging. White vegetables can nourish yin and promote fluid production, such as radish, cauliflower, lily and yam. In summer, the loss of body fluid is serious. After autumn, you should eat more vegetables that nourish yin and promote fluid production, while white vegetables are generally rich in body fluids. In the autumn diet, you should try to eat less spicy products, such as onions, ginger, garlic, leeks, peppers and so on. , and should not eat more barbecue, so as not to aggravate the symptoms of autumn dryness. The principle of "less acid and more acid" should be implemented. Avoid spicy products that hurt lung yin, mainly pepper, pepper, cinnamon, wine and so on.

After autumn, the weather is dry. People who are prone to yin deficiency and lung dryness and slow gastrointestinal motility are prone to constipation. Therefore, you should usually eat more foods that nourish yin and moisten dryness, strengthen the spleen and strengthen the stomach, such as sweet potatoes. Sweet potato is flat and sweet, and enters the spleen and kidney meridian; Has the effects of invigorating the middle energizer and blood, invigorating qi and promoting fluid production, invigorating stomach and relaxing bowels. In addition to sweet potatoes, sweet potato leaves are also rich in vitamin C and iron, and you can almost meet the needs of one day as long as you eat a plate.

Proper exercise: the cool autumn is coming slowly, but the fitness exercise can't stop all year round. Sports experts suggest that bodybuilders can choose jogging, mountain climbing, ball games and other sports that are more suitable for autumn and winter according to their physique and hobbies. Compared with summer, the amount of exercise in autumn and winter can be appropriately increased and the exercise time can be lengthened, but attention should be paid to gradual progress.