Learning Objectives:
To investigate the relationship among leaf surface area, number of stomata, and the rate of transpiration
To design and conduct an experiment to explore other factors, including different environmental variables, on the rate of transpiration
To investigate the relationship between the structure of vascular tissues (xylem and phloem) and their functions in transporting water and nutrients in plants
Before doing this laboratory you should understand:
a) How water moves from roots to leaves in terms of physical/chemical properties of water and the forces provided by differences in water potential
b) The role of transpiration in the transport of water within a plant
c) The structures used by plants to transport water and regulate water movement
Before attempting to answer these questions READ the PowerPoint on my website, and then do the key concepts on the virtual lab: Lab Bench Activity # 9
PreLab Total Points: 94 POINTS
1. What is a ‘potometer?’ (1 point)
2. Diagram and label a potometer (4 points)
3. Why and how will you measure the area of leaves used? (2 points)
4. Name three functions of transpiration. (3 points)
5. How is the molecular structure of water significant to the transport of water in plants? (4 points)
6. Explain the purpose of each of the following with regard to transpiration. (6 pts)
a. Cuticle:
b. Guard cells:
c. Leaf hairs:
7. When you receive a bouquet of flowers, it is recommended that you cut a couple of inches off of the stems before placing them in a vase. Why do you think this is? (4 points)
8. One of the following statements is not true. Decide with one is false and explain your answer. (4 points)
“The guard cells of non-desert plants often close during the daytime and open at night to conserve water.”
“The guard cells of desert plants often close during the daytime and open at night to conserve water.”
9. Which conditions will transpiration occur quicker than