Why does the sunflower's disc rotate along with the sun?
Sunflower blooming from before this period of time to germination is indeed to the disk, the disk, leaves and follow the sun in the daytime from east to west, but not immediately follow, botanists measured, pointing to the disk of the sun behind the approximately 12 degrees, 48 minutes. As the sun goes down, the sunflower's disk slowly returns, facing the east at about 3 in the morning, waiting for the sun to rise.In the sun's rays, the auxin rises on the side of the sunflower, stimulating the back surface cells to elongate and slowly move toward the sun. After the sun goes down, the auxin re distributes and turns the sunflower back to its starting position, that is, the east.However, once the disk is no longer the bloom after rotation, but the fixed toward the east. Why does it end up facing the east rather than the other way up or down? This may be the result of natural selection, beneficial to the reproduction of sunflowers. Sunflower pollen, afraid of high temperature, if the temperature is higher than 30 degrees Celsius, will be burned, so fixed toward the East, you can avoid direct sunlight at noon, reducing radiation. However, disk early in the morning sunlight, but can condense in the night in drying dew, reducing the possibility of fungal invasion, but in the cold morning, in the sunlight the sunflower disc became warm, can help attract insects to stay where pollination.The distribution of sunflower receptacle of auxin so backlight, backlight side stem growth, stem from the light source will bend
Sunflower has a strange growth hormone, which is afraid of the sun, and it always hides behind sunflower. So, in order not to let the sun dry, the auxin can only follow the sun
