Why do many white flowers open in the sky, close at night and open again the next day?

This is a way for plants to protect themselves. First of all, enclosed flowers can resist the cold and bad weather at night and avoid the harm caused by bad environment to flowers; Secondly, closing flowers can separate dew from petals and keep pollen dry, so that dried pollen can stick to insects passing by during the day to achieve the purpose of pollination;

Third, most flowers are closed at night, which can prevent moths or some bats from collecting pollen at night and wasting it. Of course, some flowers are mainly pollinated by moths, so they bloom at night and close during the day, such as epiphyllum. Many succulent landscape plants belong to Sedaceae, and their stomatal regulation mechanism is really interesting. First of all, the key of stomatal regulation is to balance the absorption of CO2 and the loss of water, so stomata are affected by internal signals and external environment.

Normal reaction to the surrounding environment. When plants close their leaves at night, they can reduce heat loss and water evaporation, thus having the function of heat preservation and moisture retention. The temperature at night is much lower than during the day, and the flowers of water lilies are closed at night to prevent the delicate stamens from being frozen. So plants sleeping at night is also the result of natural selection in the process of evolution.

Among them, CO2 concentration, illumination and humidity are the most critical. 1940, some scientists found that the increase of CO2 would lead to the decrease of stomata. Later, many experiments proved that the concentration of CO2 in cells can adjust the size of stomata, with exceptions. Some reports have proved that some plant varieties are greatly influenced by environmental humidity, but not this regulation.