– Stomata normally open during light and close during the night. – Its main function is the exchange of gases by opening and closing the pores in the leaves. – It helps in removing water from the leaves. – It takes carbon dioxide and gives out oxygen during the process of photosynthesis.

Stomata are the tiny openings present on the epidermis of leaves. In some of the plants, stomata are present on stems and other parts of plants. Stomata play an important role in gaseous exchange and photosynthesis. They control by transpiration rate by opening and closing.

Functions of the stomata They allow the exchange of gases (CO2 and O2) with the atmosphere. Evaporation of water from the leaf surface occurs through the stomata. Thus, the stomata help in the process of transpiration. Based on the climatic conditions, it closes or opens its pores to maintain the moisture balance.

The turgor pressure, which is caused by the osmotic flow of water in the guard cells, controls the opening and closing of stomata. Guard cells become flaccid as they lose water, causing stomatal closure. Stomata usually open when the leaf is exposed to light and close at night.

The opening or closing of stomata occur in response to signals from the external environment. There is a pairs of Guard Cells on each side of each stoma [singular of ‘stomata’]. They open during the day and close during night. This allows the cells to bend on one side when they become turgid.

guard cells

When the guard cells are swelled because of water absorption, it leads to opening of the stomatal pores. Once the water is lost, the guard cells become flaccid and the stomata closes. Also, during the daytime stomata generally remain open and during the night they remain closed.

If stomata are closed in plant then the plant will not be able to exchange the gases like carbon dioxide and oxygen and then due to this they will be not able to perform photosynthesis and then will naturally die because of no food and nutrients.

night

and the apertures decreased slightly at higher tempera- tures. Stomata do not appear to close at midday in leaves of most species at air temperatures of 36 “C or lower provided that the leaves are not under water stress.

All species responded in the same way. The opening of stomata with increasing temperature was apparently independent of the stomatal response regulated by atmospheric humidity. At high plant water stress, the stomatal response was reversed, i.e., the stomata closed when temperature was gradually increased.

Jade plants, succulent plants, pineapple, Keep stomata CLOSED during the day and OPEN at night. Store carbon dioxide as an organic acid. The organic acid then releases carbon dioxide directly to the Calvin Cycle.

At night, the stomata close to avoid losing water when photosynthesis is not occurring. During the day, stomata close if the leaves experience a lack of water, such as during a drought.