Laboratory Investigation # 7
Transpiration
Description of the Lab
This lab is to demonstrate some aspects of transpiration in plants. To see the
Outline of Investigation
1. Stomata
2. Transpiration
A. Celery or mum stems, flask, razor blades, microscope slides, coverslips
& 1% eosin stain
3. Stomata and Light
A. Six 10 mL graduated cylinders per pair of students
Six stems of the same type plants
Suggestion: Use 2 or 3 different plant stems which can add a
dimension of experimentation to the lab. You could use the celery
stem on hand.
Laboratory Materials and Equipment for Student Use
Materials and Equipment
Per
Student
Per Pair of
Students
Per Lab
Group
Per
Room
Razor blades
1
Microscope slides and coverslips
1 box
10 mL graduated cylinders
6
plastic wrap
2 boxes
Reagents
1% eosin stain
1. Weigh 1 gram of eosin stain
Preparation of laboratory Materials and Reagents
Grow plants at the beginning of the semester.
1 day prior to the lab
1. Gather together of graduated cylinders, plastic warp and bright lights.
After the Lab has finished
sunny window sill or grow lights
6
Potted geranium (Pelargonium) plant
1
7
Leaf and stem cross sections
1
1% eosin stain
2 L
Questions for Lab #7 Transpiration
Use the knowledge you acquired in this lab exercise, along with information from your
textbook, to answer the following questions.
1. What are stomata and what are their functions?
Stomata are openings in the leave’s epidermal layer and they function in admission of
2. How are stomata related to Transpiration?
Stomata are opening that allow for release of water from the leaves in the process of
3. What are guard cells and how do they affect the opening and closing of the stomata?
4. How does water pressure with in the guard cells affect their function?
Guard cells provide a reservoir of water and ion that move in and out changing the
5. Are both xylem and phloem both involved in transpiration? If so, how are they
involved?