AP Biology Lab 9A Alternative Version: Whole Plant Transpiration.
Materials list
 Minimum 16 Bedding plants (Marigolds, Petunias, or any that are inexpensive
and available)
 Scale
 Graduated cylinder
 Flood light
 Heat sink: Large Ehrlenmeyer Flask or Beaker
 Fan
 Spray Bottle
 Labeling tape and markers
 String or twist ties
 Small plastic bags.
Procedures
1. Select 4-5 plants for each of the four testing areas. Try to make sure
that the groups are even in size and amount of leaves on the plants.
2. Remove any of the blooms that are on the plant. If any blooms or
leaves fall off of the plant during the experiment, they should be
placed into the center of the plant so that the mass is not adversely
affected.
3. Place the root ball of each plant into a small plastic bag.
4. Add 10 ml of water to the bag.
5. Tie of the bag to the base of the stem with string or twist ties.
6. Mass and record all of the groups of plants.
7. Set the plants back into their containers.
8. Mist one group of plants heavily with the spray bottle and place under
an upside down aquarium. Place a tray of water under the aquarium to
maintain the humidity.
9. Set up the heat sink, between the next group of plants and the flood
light. The light should be one meter from the plants.
10. Place a fan, set on low, one meter from the next group of plants.
11. Place the last group in an area with moderate light and no drafts.
12. Leave all groups in place for the duration of the experiment.
13. Record the final mass of the groups.
14. Plot the change in mass for the groups.
15. Remove from the plastic bags, replace into containers and take home.
16. Plant!!