1. Stomata Lab WARNING: Do Not leave the pipette in the little cup, it will tip over!!

2. This lab is on Page 640 Cover slip Clean slide Tap water pipette Lens tissue Paper towel

3. This lab focuses on careful observation of the upper and lower epidermis The eye-shaped openings (stomata) in the lower epidermis of a spinach leaf allow gas exchange and help control water loss. The upper epidermis protects the photosynthetic tissues below. Procedure: 1.Make a wet mount by tearing a leaf at an angle to expose a thin section of epidermis. 2.Use the tap water provided to make a wet mount of both the upper and lower epidermis.

4. Observe Each person at a lab table needs to hand in their own paper. Examine both the upper and lower epidermis slide preparations under the microscope. Draw or take down a written description of what you see.

5. Analysis On your paper, answer the following questions: 1.a. What do the cells of the leaf epidermis look like? b. What is their function? 2.a. How do the epidermal cells differ from guard cells? b. Which cells, if any, contain chloroplasts?

6. Focus a stomata under high power When you have one, call Mrs. D over to add a little salt water to your slide. Take turns observing the changes in the stomata as the salt water causes the stomata to empty of water.

7. Analysis On your paper, answer the following questions: 3.a. What differences in the stomata did you notice when you added a salt solution to the cells? b. Can you explain what happened in terms of osmosis?