Why do sunflowers face the sun?

Sunflowers facing the sun

It is an interesting phenomenon that sunflowers turn towards the sun. Because once it encounters light, it will rotate with the sun. However, this refers to the period from germination to blooming of the plant. Its leaves and flower disks will change from east to west with the rotation of the sun. After the flower pot blooms, it will no longer rotate, but will remain fixed facing the east.

In fact, although the flowers and leaves of sunflowers rotate with the sun, this is not actually synchronized in real time. Scientists have measured that their rotation lags slightly behind the sun. When it rotates, it will rotate westward as the sun rises in the morning. After the sun sets, its disk will slowly swing back, and at about 3 o'clock in the morning, it will turn back to the east.

Why face the sun?

The main reason for rotating towards the sun is the influence of light.

The auxin of sunflower is distributed on the tip of the stem and is constantly transported downward. It is affected by light. Generally speaking, its auxin is distributed against the light. The concentration is relatively low on the side facing the sun, but relatively high on the side facing away from the light. Therefore, the side facing away from the light grows faster, while the side facing the light grows slower, causing the stem to bend against the light, so that it always faces the sun.

In addition, people also believe that the reason why sunflowers rotate towards the sun is related to gravity and chlorophyll. The gravity aspect refers to the fact that it will rotate with the sun in the early stages of growth and in the young period of the flowerpot; the chlorophyll oxidase aspect refers to the fact that this substance can hinder the growth of sunflower cells. Generally, the concentration of chlorophyll oxidase is higher on the side facing the light, so the side of the sunflower facing the light will grow slower, causing it to bend.

Well, this is how sunflowers grow towards the sun. Isn’t it amazing?