Investigation of Leaf Stomata
Lab Experiment for Section 5.2
Please remember…
• stoma = singular.
• stomata = plural.
Pre-Lab Questions:
1.) What is the primary structure of
stomata? Please draw and label a
picture. Where are stomata located on a
plant leaf?
• Stomata (small openings) are typically
scattered about the lower epidermis
(underside of leaf). Each stomata is
surrounded by a pair of guard cells
Your drawing should be based on this
image.
Pre-Lab Questions:
Pre-Lab Questions:
Pre-Lab Questions:
2.) What is the primary
function of stomata?
• Stomata allow for the plant
to “breath”.
Pre-Lab Questions:
3.) What enters the leaf through the
stomata? What exits the leaf
through the stomata?
• Through these holes…
1. carbon dioxide enters the leaf.
2. water is released (transpiration).
3. oxygen is released.
Pre-Lab Questions:
4.) What happens to the stomata when
guard cells swell? What happens to the
stomata when guard cells shrink?
• 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.
Pre-Lab Questions:
Post Lab Questions:
1. Will plants have more stomata open
during the day than during the night?
Explain.
• Generally, stomata work on a regular
day and night cycle where each stoma
opens during the day and closes again
at night. (Exceptions to this rule occur
in desert plants.)
Post Lab Questions:
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. (You should
form 2 hypotheses.)
• If a plant is kept in the dark, then the number of open
stomata found on the plant leaves will decrease.
• If a plant is kept in the light, then the number of open
stomata found on the plant leaves will increase.
Post Lab Questions:
3. Answer the following questions by referring to
the image provided.
Post Lab Questions:
• Write the number & name of the
structure(s) that regulate the opening &
closing of the stomata.
• 8 - guard cells
• Which number indicates where oxygen exits
the leaf?
• 9 - stomata, same place where water exits
and carbon dioxide enters