Sunflower stems contain a wonderful auxin. This auxin is very afraid of light. When it is irradiated by light, it will go to the backlight side and stimulate the cells on the backlight side to multiply rapidly. Therefore, the backlit side will grow faster than the bright side, which will bend the sunflower to light.

Sunflower has obvious phototaxis, and its front faces the sun, so the good flower shape is often smooth, while the flowers with side light or backlight are often ... Because of the refraction of petals, the inside of the bud is warm orange-red, with yellow and white stamens, the color is harmonious and full of vitality.