Purpose-To observe the shape of stomata and the functioning of the guard cell. 

Materials needed-Lettuce leaves, forceps, water, microscope slide, cover glasses salt water, video microscope

Procedure-

1. Peel the skin of the lettuce and place the skin in the slide.
2. Make a wet mount of the skin or epidermis of lettuce leaf.
3. Put the slide under the microscope
4. Find out the stomata and fix a good section of the leaf to be observed under video microscope.
5. Observe and count the number of open stomata and close stomata.
6. To the same section of the leaf add 2-3 drops of salt water through the sides . Wait for 2-3 minutes.
7. Observe the stomata and count the number of open and close stomata.

Observation

	Water mount	Salt solution
No of open stomata
No of close stomata
Drawing of leaf section

Conclusion

1)What are guard cells?

2)Why did stomata close in the presence of salt water?

3)The number of open stomata were larger in ----------------- water.

Activity 2

Approx. time :setup- 15 mins, observation time- 3-4 days

Purpose: To verify that more stomata are located on the lower side of the leaf than on the upper side.

Materials needed: Two potted plants,Vaseline , graduated cylinder,two plastic bags and rubber band.

Procedure;

1. Keep two potted plants side by side.
2. Label them as 1 and 2.
3. Water the two plants(about the same amount of water)
4. Keep them in a place where they get a lot of sunshine
5. Put Vaseline on the upper side of a leaf in pot 1 and in lower side of a leaf in pot 2.
6. Cover the leaf (both in pot1 and pot 2) to which vaseline has been applied with a clear plastic bag.
7. Tie the open ends to make it air tight.
8. Check the amount of water collected in both plastic bags. After 3-4 days

measure the amount of water in both bags using a graduated cylinder.

	Leaf in which vaseline was applied on lower epidermis
	leaf in which vaseline was applied on upper epidermis

This experiment was set up,photographed using digital camera and inserted in the web site by Rahika Plakkot

Observation	Amount of water collected in ml
Leaf in which Vaseline was applied on lower side
Leaf in which Vaseline was applied on upper side

Conclusion

1)Which plastic bag contained more water?Why?