Download Stomata lab data sheet

Investigation of Leaf Stomata
Lab Experiment for Section 5.2
Purpose:
In this activity, you will be investigating the structure of the stomata within a spinach plant leaf
and determine how it functions with regards to the process of photosynthesis.
Objectives:
 Students will be able to define the function of the stomata
 Students will be able to investigate the presence of stomata on spinach leaves during a lab
experiment
Background Information:
Scattered about the lower epidermis are small openings called stomata. It is through these holes that
carbon dioxide enters the leaf, & oxygen & water vapor exit.
Each stoma is surrounded by a pair of guard cells. When guard cells swell, the stomata open,
when the guard cells shrink, the stomata close. Plants respond to changes in temperature &
humidity by opening or closing
their stomata (an example of
maintaining ... homeostasis).
Pre-Lab Questions:
1.) What is the primary structure of a stoma? Please draw and label a picutre. Where are stomata
located on a plant leaf?
2.) What is the primary function of stomata?
3.) What enters the leaf through the stomata? What exits the leaf through the stomata?
4.) What happens to the stomata when guard cells swell? What happens to the stomata when
guard cells shrink?
Procedure:
1. Obtain a spinach leaf
2. Paint a thin patch of clear nail polish on the underside of the leaf. Make a patch at least one
square centimeter.
3. Allow the nail polish to dry completely.
4. Tape a piece of clear tape to the dried nail polish patch. (The tape must be clear. Do not use
Scotch tape or any other opaque tape. Clear carton-sealing tape works well.)
5. Gently peel the nail polish patch from the leaf by pulling on a corner of the tape and peeling
the fingernail polish off the leaf. This is the leaf impression you will examine.
6. Tape your peeled impression to a very clean microscope slide.
7. Examine the slide under a microscope at the highest level of magnification possible (exposing
cell details)
-Identify the following cell details: stomata and guard cells
-Determine the number of stomata cells present within that small section of the leaf,
record value here _____________________
-Draw a picture of what you see
8. When finished, peel the piece of tap off of the slide and dispose of. Clean slide thoroughly
Post Lab Questions:
1. Will plants have more stomata open during the day or during the night? Explain
2. Develop a hypothesis about the number of open stomata found in a plant kept in the dark
compared to a plant in the light. Write your hypothesis below, and make sure that it is a complete
sentence. (should form 2 hypotheses)
3. Answer the following questions by referring to the image provided.
Write the number & name of the structure(s) that regulate the opening & closing of stomata.
Which number indicates where oxygen exits the leaf?