The CO2 enter into the leaves it only depends upon the stomata opening. The guard cells are use to the opening and closing of stomata because of their strange structure and changes in their shape. Stomata are adaptable pores that are usually open during the day when CO2 is required for photosynthesis and closed at night when photosynthesis stops.
Opening of stomata:
Guard cell contain chlorophyll, thus they are the only photosynthesizing cells of the epidermis. At daytime when guard cells absorb carbon dioxide, some of it reacts with water in which it is dissolved to form carbonic acid.
When light is present, carbonic acid in the guard cells decomposed again into carbon dioxide and water, which are rapidly used to form carbohydrates. These carbohydrates are sugars and have phosphate groups. They become turgid and curve apart. In this way a stomata or pore forms between two guard cells.
Closing of stomata:
In dark or at night sugar molecules of the guard cells are either removed by respiration or converted into insoluble starch. At the same time acid content of the cell increases. As sugar molecules are removed from the guard cells, the water in the guard cells increases. When guard cells lose water, they become less turgid. The inner walls then move together until the pore between them is closed.
Opening of stomata:
Guard cell contain chlorophyll, thus they are the only photosynthesizing cells of the epidermis. At daytime when guard cells absorb carbon dioxide, some of it reacts with water in which it is dissolved to form carbonic acid.
When light is present, carbonic acid in the guard cells decomposed again into carbon dioxide and water, which are rapidly used to form carbohydrates. These carbohydrates are sugars and have phosphate groups. They become turgid and curve apart. In this way a stomata or pore forms between two guard cells.
Closing of stomata:
In dark or at night sugar molecules of the guard cells are either removed by respiration or converted into insoluble starch. At the same time acid content of the cell increases. As sugar molecules are removed from the guard cells, the water in the guard cells increases. When guard cells lose water, they become less turgid. The inner walls then move together until the pore between them is closed.