Sunflower Flowers moving towards the sun? Actually, the stem is moving. Why is it facing east when it's ripe?
Many people know that sunflower flowers move with the sun, but not as ordinary people think. Many people have seen some sunflower animations, and the flowers (flower plates) will rise with the sunlight and continue to rotate with the sunlight.
In fact, before the sunflower blooms, its stems and leaves will respond to light, which is positive (light causes the growth hormone at the tip of the plant bud to move to the side of the backlight, so that the backlit side grows faster, and the phenomenon of sunward appears).
The other is phototropism, where most of the stems and leaves of the ground part of the plant grow towards the sunny side.
Sunflower flowers with the continuous movement of the sun, in fact, only occur in its rapid growth stage (that is, germination until the flower is not mature), the reason for this phenomenon is actually the growth (kin) of the plant at work.
- Auxin and lutein
During the day, the sunflower stem will get more auxin on the side that is slightly backed by the sun, which is also called growth hormone, and the auxin runs to the backlit side, and the stem on the side facing the sunlight grows slowly, and the backlit side of the stem grows faster.
There is also a chlorophyllum in the stem of the sunflower, which inhibits cell growth, and on the side facing the sun, it inhibits cell growth. On the backlit side, there is auxin to increase the growth rate, and the combination of the two causes the stem to tilt toward the sun.
That is, on a stem, the growth hormone obtained on each side is unbalanced, and it is this difference that causes the sunflower flowers to tilt towards the side of the sun.
This also explains why sunflowers can grow rapidly, its flowers will continue to move towards the sun, in fact, the sunflower's stem in the acquisition of auxin, the shady side than the yang side to absorb more auxin caused.
Mature flowers are basically facing east, no longer "turning their heads"
When a sunflower is in the stage of germination, flower maturation and seeding, the flower will stop moving toward the sun, that is, its harvest of auxin begins to stop.
- Why do you face the east in the morning?
There are also many flower lovers who will have doubts. How does a sunflower return to its east-facing position before dawn during its rapid growth phase?
This involves circadian rhythms, plants and people will have metabolism, this is the physiological changes that most organisms will have, generally 24 hours to repeat.
In the absence of sunlight, the sunflower's photosynthetic ability is weakened, the auxin in the plant gradually returns to balance, and the chlorophyllic oxide that inhibits growth loses its vitality at night, so that the sunflower's stem will return to the position where the sun rises, which will gradually move its flowers back to the east-facing position. Instead of suddenly turning the flowers to the east-facing position when the sun has just risen.
If you have seen a large field of sunflowers, in the morning you will find that their flowers are all in the position of rising towards the eastern sun.
I did an experiment where if you put a sunflower in a position where there is an obstacle, such as planting it in a corner, when the sun just rises, the sunlight will be blocked by the wall, and the sunflower flower will go to the position where it can receive the first rays of sunlight (rather than facing east), which is the self-adjustment of the plant, not that the sunflower flower will necessarily face east in the morning.
- Where do the flowers go when they mature?
After the sunflower's flowers mature, the growth stage of the stem is over, and it will not grow upwards, at this time its task is completed, and the influence of auxin and luteinin is minimal.
After the sunflower flowers are full, the flower head is particularly heavy, and some will bend the stem, not to mention following the sun to "turn its head", generally only fixed to the east (to avoid the noon and afternoon sunburn flowers, to ensure the success of pollination, is the plant's self-protection).