Since our childhood, we have always referred to the inclination of the sunflower to determine the time of day. But does the sunflower really follow the sun ? Is there a reason for this belief, or is it a delusion?
Understanding the growth of the sunflower
The sunflower has a plant hormone called auxin that sits at the top of the stem. It is responsible for the growth of the cells of this plant. The phytohormone accelerates the multiplication and differentiation of sunflowers.
Auxin moves from the stem to the root at a speed of 15 millimeters per hour. Its quantity spreads according to the lighting. Its concentration is different at the top and bottom of the stem depending on the light. As it is a hormone, which is not compatible with light, it hides from the sun as much as possible. Therefore, while the sun is up, it concentrates on the lower part of the stem. Don’t hesitate to check out our new collection of sunflower necklaces, available on our shop only !
As it is a growth hormone, the lower part of the sunflower stem grows faster than the upper part. It is this phenomenon that gives the impression that the sunflower follows the sun. In short, it is the weight of the flower that forces this inclination towards the sun.
A phenomenon that stops at maturity
When the sunflower blossoms, the green sepals are hidden behind it and become useless. The sunflower does not change its orientation when it reaches maturity. The impression that it is turning towards the sun is due to the growth hormone, which does not move when the flower is mature.
If it no longer moves, the plant freezes in the direction of the rising sun. This fixation has an advantage, however. Pollinators looking for morning warmth are more likely to turn to a flower that faces the sun first thing in the morning.
This advantage then increases the pollination of sunflowers and is even the reason they reproduce easily. However, if you see a field of sunflowers, the impression that they are turning towards the sun does not stop. Why does this happen? Because there are always young shoots that are being displaced by the growth hormone. If you are a true fan of sunflower, you can always get one of our sunflower rings right now !
A well established belief
Unless you know how the sunflower grows, it’s sometimes hard not to believe that the sunflower really does follow the sun. The sunflower is also used to determine whether the time is advanced when you don’t have a watch at hand.
Moreover, whether it turns towards the sun, the sunflower embellishes your table with a beautiful vase or your garden and even is a stunning sunflower bracelet with its colorful flower. It gives a beautiful effect on a flower arrangement. If you have planted it in your garden, it fears drought and dreads soil that is too wet. Be careful when watering it. Don’t forget also to remove the faded flowers as you go along so that they don’t damage the plant’s energy. This gesture increases its life expectancy.
Do sunflowers really follow the sun: The auxin hormone
At the origin of this movement of the sunflower towards the light, we find auxin, which is a plant hormone. Present since the top of the stem, this phytohormone lengthens the cells, favors their multiplication and their differentiation.
It moves from the stem to the root, at a speed of 15mm/h and spreads according to the luminosity by seeing its concentration decreasing from the top to the bottom.
Indeed, the auxin do not appreciate the light, and move away from it as much as possible. Thus, they will be concentrated in the lower part of the stem in sunflowers.
Since auxin is a growth hormone, the bottom of the stem will grow much faster than the top. This is what will create the impression that the sunflower is looking at the sun. If you are fascinated by the sunflower, you can always take a look at one of our beautiful sunflower earrings, to embrace this legendary flower !
It is really just the weight of the flower that will force the tilt.
Do sunflowers really follow the sun : The fixation
This effect, which is thus related to a growth hormone, will as you can imagine stop once the sunflower reaches maturity.
It will not have indeed anymore to undergo the movements of the hormone, and will thus be frozen in the direction of the rising sun.
So do sunflowers really follow the sun? Well, no!