Question

How do guard cells control opening and closing of stomata?

Answer 1

Hint:-When the water flows into the guard cells, they swell up and the curved surface causes the stomata to open. Stomata are a minute opening that is present on the leaf, stem, and other parts. Stomata are present in the leaf which helps in the exchange of gases between the atmosphere and the inside of the leaf. Stomata are the tiny, bean, or kidney-shaped openings that are present in the epidermis of the leaf.

Complete answer:
Stomata are adjustable pores that are usually open during the day when carbon dioxide is required for photosynthesis and closed at night when photosynthesis is shut down. The opening and closing of stomata are controlled by changes in the shape of the two guard cells that surround each pore. When water moves into guard cells from surrounding cells, they become turgid and bend, producing a pore. When water leaves the guard cells, they become flaccid and collapse against one another, closing the pore.
Although daylight and light and darkness trigger the opening and closing of guard cells, other environmental factors are also involved, including carbon dioxide concentration. A low concentration of CO$_2$ concentration on stomatal opening, are interrelated. Photosynthesis, which occurs in the presence of light, reduces the internal concentration of CO$_2$ in the leaf thus triggering stomatal opening. Another environmental factor that affects stomatal opening and closing is dehydration. During a prolonged drought, stomata opening and closing are also under hormonal control.

Additional information:-
Functions of Stomata:
- Stomatal opening helps in the exchange of gases between plants and surroundings.
- It helps in transpiration and helps to remove an excess of water in the form of water vapor.
- Stomata help to maintain moisture content by opening and closing guard cells.
- Stomata help in the process of photosynthesis by the uptake of carbon dioxide and release of oxygen.

Note:- The opening and closing of the stomata take place through the stomatal pore. An internal biological clock that measures time may regulate the opening and closing of stomata. After plants are placed in continuous darkness, their stomata continue to open and close at more or less the same time each day. Such rhythms that follow an approximately 24-hour cycle are known as circadian rhythms. There are so many types of stomata present based on their numbers, size, and shape.