ASIM K8 Lab:
Estimating # of Stomata in a
Lettuce Leaf
By: Lisa M. Clark
TCHS

Stomata
• Structure
• Tiny pores located on bottom of leaf
• Oval shaped
• Function
• Release extra water from the leaf
(called transpiration!)
• Look a little bit like cat eyes!
• Two kidney-shaped cells
(guard cells) are found on each side of the stomata.
• Chloroplasts are also found in the guard cells.
• Take in carbon dioxide
• Release oxygen
• Guard cells swell & shrink to control the opening & closing of stomata
• Chloroplasts within guard cells carry out photosynthesis.

Click to the next slide to view a video that explains and shows the function of stomata.

a) 100X Total magnification
A magnified section of the leaf you see in figure b. Notice there are about 18 stomata.
b) 40X Total magnification
The underside of a leaf
(not enough magnification to see the stomata).
http://www.pnas.org/content/101/4/918/F1.large.jpg

This picture also shows the lettuce leaf’s lower epidermis (~400X) http://www.lima.ohio-state.edu/biology/images/stoma.jpg
• The labeled parts are what you will identify in lab.

Lower Leaf Epidermis (~1000X)
• This picture shows a plant leaf’s lower epidermis under the microscope.
• Look carefully at the labeled parts.
• These are the parts that you will label during lab.
www.tutorvista.com/.../protective-tissues.php

Labeled diagram of stomata
& surrounding guard cells http://image.tutorvista.com/content/plant-water-relations/stomatal-movement--dicot-plants.jpeg