Does a sunflower follow the sun during the day and really shake its head back to its original position at night?

Of course, a sunflower won’t swing its head back to its original position at night. Of course, it doesn’t want to scare you, let alone sprain its own neck. That's a joke, and the answer is yes, it will return to its original position, but not by jerking its head.

First of all, you need to be clear that not all sunflowers will follow the sun. Only immature sunflowers will follow the sun, and they do not follow the sun every day. There is a hormone called auxin in plants that regulates plant growth and development. The location where the appropriate concentration of auxin exists can promote the growth of the plant at that location. The reason why the sunflower rotates is mainly due to the uneven distribution of auxin.

A suitable concentration of auxin is distributed in the young sunflower stems. The distribution of auxin is mainly affected by sunlight and gravity. When there is light, light has a greater regulatory effect on auxin, and plants show phototropism at this time. When the sun shines from one side, there is less light on the other side, and auxin accumulates on the side with less light, causing the stems on the backlit side to grow faster and the stems bend, allowing the flower disk to face the light. direction of coming.

But at night, the light factor disappears and the gravity factor takes over. The auxin originally accumulated on the backlight side sinks to the light side due to gravity, allowing the light side that grows slower during the day to grow faster at this time, so the sunflower will slowly raise its head and return at night. to the east direction. Of course, the flower disk does not rotate every day. If it rotates at a larger angle one day, it may have to stop and rest for a few days before continuing to follow the sun.

Mature sunflowers generally do not continue to rotate with the sun. They generally maintain a stable eastward direction until the flower disk is fully mature.