Why does sunflower face the sun?

Sunflower roots contain a substance called auxin. This kind of room has two characteristics, avoiding light and stimulating cell growth. It is located in the neck of sunflower. Every time it meets the sun, it will run to the side of the backlight and hide. Because it has the function of promoting growth, the back will grow faster than the sunny side, resulting in the disk always facing the sun at the earliest.

A scientist once did an experiment to replace the sun with a brazier, but in the experiment, the fire was blocked by an object, so that the sunflower could not determine which side was sunny. However, when the brazier moves, the sunflower disk will also move with it.

Scientists believe that sunflower flowerpots are very sensitive to heat. When the tubular floret is heated by the brazier, the fiber will shrink, which eventually leads to the flowerpot turning to the brazier, which is why the sunflower faces the heat source.

Sunflower, also known as sunflower, was once a symbol of the sun god in the ancient Inca Empire. Sunflower is listed as the national flower in Russia, Peru and other countries, and is deeply loved by people all over the world. This is not only related to the efficacy and function of sunflower, but also related to its special significance. The flower language and meaning of sunflower are the voices of many people. It is said that Putin's favorite plant is sunflower, which shows how far-reaching its moral influence is.

Extended information: Introduction to Sunflower:

1. Sunflower (Latin: Helianthus annuusl.) belongs to the genus Panicum in Compositae. 1 ~ 3.5m high. The stems are erect, round and angular, hard and covered with white coarse bristles. Leaves broadly ovate usually alternate, apex acute or acuminate, base with 3 veins, margin coarsely serrated, both sides rough, hairy and long handle. Head inflorescence, diameter 10 ~ 30 cm, solitary at the top of stem or branch.

2. The involucral bracts are multi-layered, leafy, imbricate, long setae, flowering in summer, with neutral yellow tongue-shaped flowers at the edge of inflorescence, which do not bear fruit. The middle of the inflorescence is a bisexual tubular flower, brown or purple, which can bear fruit. Achenes are oval, lignified, gray or black, and are called sunflower seeds. ?

3. Native to South America, the domesticated species was brought to Europe from North America by the Spanish in 15 10, and was originally used for viewing. /kloc-It was introduced back to North America from Russia at the end of 0/9. It was cultivated in China. Sunflower seeds are called sunflower seeds and are often fried as snacks. They are delicious, sunflower seed oil can also be squeezed out to eat, and oil residue can be used as feed.

Sunflower, also known as sunrise flower, is named because its flowers often face the sun. Although the English name of "Sunflower" is related to its Japanese characteristics, the name mainly comes from its golden flower that looks like the sun when it blooms, which was borrowed and translated from the Latin sunflower "Flossolis" from16th century to17th century. The French, Italian and Spanish names of sunflower are tournesol, girasol and girasol respectively. Like China people's names, they are all named according to the feature of "facing the sun".

5. Sunflower is really sunny from germination to disk flowering. During the day, its leaves and disk follow the sun from east to west, but not immediately. According to the botanist's measurement, the direction of its disk surface is about 12 degrees behind the sun, that is, 48 minutes. After the sun goes down, the sunflower tray slowly swings back, facing east at about 3 am, waiting for the sun to rise. ?

6. Under the irradiation of sunlight, the auxin content on the back of sunflower increases, which stimulates the cells on the back to elongate and rotate towards the sun. After the sun goes down, auxin is redistributed, which makes sunflower turn to the east again. After the disc is in full bloom, it no longer turns to the sun, but is fixed in the east. Sunflower pollen is afraid of high temperature. If the temperature is higher than 30℃, it will be burned.

7. So fixing it in the east can avoid direct sunlight at noon and reduce radiation. When the disk is exposed to sunlight in the morning, it helps to dry the dew condensed at night and reduce the possibility of being attacked by mold; In addition, the temperature is low in the morning, and the sunlight makes the sunflower tray a warm nest, which can attract insects to help pollinate.

8. The auxin in sunflower receptacle is distributed in the backlight, so the stem on the backlight side grows faster and bends towards the light source. Sunflower, named after the tip of its young plant in the early growth stage and the young disc in the middle growth stage, will obviously rotate with the sun. It is believed that the sunrise of sunflower is only related to light and gravity. ?

9. Plants will produce a wonderful auxin, which is mostly concentrated in vigorous growth parts and less in aging tissues and organs. Can promote (inhibit) the growth of cells, accelerate (slow down) the division and reproduction of cells, backlight, and run to the backlight when exposed to light. Polar transportation, from the upper end to the lower end of the form, is irreversible.

Reference: Baidu Encyclopedia Sunflower