A photo from open sources
If you ever walked in the garden in the evening, then probably noticed that some flowers “fall asleep” after sunset, closing their buds. Plants that “fall asleep” at night time, do what science is called “nikinastiya” (flower movement under the influence of light and darkness) and this is completely natural. To scientists the mechanism of this phenomenon is known: in cool air and darkness the lower petals of certain colors grow faster than the upper petals, making the flowers close. It’s not clear why some plants, especially flowers, develop in this way. However, there are several theories. Charles Darwin believed that plants close overnight to reduce the risk of freezing. Another theory suggests that plant nikinastia serves to preserve energy and possibly odor for daytime when pollinating insects are most active. Some scientists believe that this process does not allow pollen to become wet and heavy due to morning dew. It is easier for insects to carry dry pollen, therefore Niktinasty is the key to successful reproduction. Another fascinating the theory claims that niktinasty is a highly developed mechanism protection against nocturnal predators. Closing tight, the flowers create visibility of thick grass, becoming invisible to such nightly hunters like owls that kill a flower by chewing it in searching for small animals. Anyway, all these devices the flower only strengthens its defense to reduce the level damage to pollen and the flower itself. Of course it’s also an additional evolutionary advantage for a plant living in resource-limited world.
Sergey Vasilenkov
Time Insects Plants
