Lab: All Things Photosynthesis
Investigation A: Investigating Stomata
Learning Goals: write out completely in lab book
1. Students will be able to diagram the stomata, identifying the opening and the guard cells.
2. Students will be able to describe the function of the stomata in the process of photosynthesis.
3. Students will be able to describe the conditions in which stomata are open or closed and be able to
accurately describe the role that water plays in this process.
4. Students will be able to identify where stomata are located for plants.
Prelab:
1. Draw and label a cross sectional diagram of a leaf and label all of the parts.
2. Diagram the parts of stoma labeling the guard cells and opening.
3. Write a prediction about the stomata (size, location, and placement) for the plant selected. Represent
the prediction in a graph format.
Science Journaling:
Write out the procedures followed to observe stomata under the microscope. DO NOT include a list of
materials but rather incorporate them into the procedure to follow. Collect all qualitative and
quantitative data from the experiment.
Procedure:
1. Review procedures on the opposite side of this paper
2. Estimate size of field of view at different magnifications
a. Using a scale slide 10mm by 10mm
b. Measure the diameter of the field of view at 40x and 100x magnifications.
c. Calculate the area of each field of view using the diameter
3. Predict the # of stomata expected to be seen in a single field of view
a. 100x – top side of leaf
b. 100x – bottom side of leaf
4. Observe the top and bottom sides of a leaf on both 40x and 100x. Record the number of stomata
observed on each side. Describe the system used to count the number of stomata.
Postlab Assessment:
1. Present data in a clear table format with appropriate headings and titles.
2. Why was data only recorded at 100x magnification?
3. What conditions allow the stoma to be open or closed to the environment? Describe how these
conditions make the stoma open and close.
4. In a paragraph, incorporate research about stomata with findings from investigation to describe the
role the stomata plays in plant processes.
Data Analysis:
1. Compare the data to the prediction. Using the data make a claim about stomata. Cite evidence (data)
from that collected to support the claim. Justify why the data supports the claim.
2. Do you think the number of stomata would vary from plant species to plant species?
3. In general, more stomata are found on the bottom of leaves versus the top of leaves. Why do you think
this is the case?