Name: _________________________ Period:_______

Stomata Lab Purpose:

To observe stomata in a living leaf.

Procedure: 1) Make a wet mount slide of a piece of leaf. We want to look at the bottom side of the leaf. 3) Observe the slide under low power and medium power. Using medium power, make a detailed drawing showing the different kinds of cells you see. Include at least one stoma. Notice the shape and arrangement of the stomata. Place a stoma at the center of your field of view. 4) Observe the stoma under high power. Make a detailed drawing of the cells. Label the STOMA (opening), the GUARD CELLS, and any other parts you can see (like leaf cells and chloroplasts). Observations:

(Draw all the cells in your field of view on drawing 2.) Label the STOMA, the GUARD CELLS and any other parts.

Underside of Leaf

X

Underside of Leaf

X

Questions: 1) On medium power, compare the stomata to the other cells in the leaf. How do the number and shape of the stomata compare with the number and shape of the cells around them? ____ stomata (openings) and _____ leaf cells = _____ ratio Describe the shape of guard cells:

Describe the shape of leaf cells:

2) What causes the guard cells to swell or shrink, controlling the stomata? Explain how:

3) Why are the stomata open during photosynthesis?

4) Are the stomata usually open or closed during dry periods? Explain why!

5) How does the ability to open and close the stomata aid in the survival of the plant through different types of weather? Use #3 and #4 for help.