Teacher explains to the students about the stomata, their role in plants processes and the factors affecting the opening and closing of the stomata

STOMATA

Stomata also called stoma(singular) are the microscopic openings or pores in the epidermis of the leaves. Stomata's are generally seen in abundance in the lower side of the leaf.(Ref to the lab activity)

GUARD CELLS

The stomata are surrounded on each side by two large sausage shaped cells called d guard cells. Guard cells control the opening and closing of stomata. Water moves into and out of the guard cells by osmosis. When guard cells absorb water they swell and stomata opens. When guard cells lose water, they relax and stomata close.

	Picture of an open stomata.
	picture of a closed stomata

Slides made and inserted into the web page using video microscopy by Rahhika Plakkot.

ROLE OF STOMATA IN TRANSPIRATION

Loss of water vapor through stomata of a leaf is called transpiration. Darkness,internal water deficit and extremes of temperature tend to close stomates and decrease transpiration. A tree like the date palm may transpire more than 500 litters of water in a single day.

ROLE OF STOMATA IN PHOTOSYNTHESIS

Photosynthesis is the process in which plants use energy from light to produce food with the help of carbondixide , water and from chlorophyll present in the leaves. Stomata play an important role in photosynthesis in plants. The carbon dioxide necessary for photosynthesis enters into the leaves through the stomata. In the presence of abundant carbon dioxide and in the availability of light the guard cells expand and the stomata open to let carbon dioxide in. This carbon dioxide is later used in photosynthesis by the plants.

THE FACTORS AFFECTING THE OPENING AND CLOSING OF STOMATA

1. carbon dioxide
2. light
3. water
4. humidity
5. type of plant
6. wind
7. photo period