KENNEDY

AP\IB BIOLOGY

Photosynthetic Surface Area Lab

Introduction:

Photosynthesis is the process that plants use to produce starch and sugars. These compounds are later used in cell respiration to allow the plant to grow. Photosynthetic surface area of a plant is the area within the plant that is available for photosynthesis. This surface area controls the spread of plant growth and in part its final size as an adult. The amount of surface area can also tell you a great deal about the plant's requirements for growth and physiology.

Procedure:

1. Locate tree to sample and identify it.

2. Record any outwardly noticeable characteristics of the tree, i.e.. leave color, size, shape, tree height, et...

3. Select several mature leaves from the tree.

4. Trace them on a piece of graph paper

5. Estimate surface area by establishing a scale (cm) for your graph paper and counting the number of boxes within the tracing of your leaf.

6. Repeat step 5 at least 5 times and average your totals.

7. Select several branchlets and estimate the average number of leaves per branchlet.

8. Select several branches and estimate the average number of branchlets per branch.

9. Estimate the number of branches on your tree.

10. Multiply steps 7,8,9 to get the number of leaves possible per tree.

11. Multiply this number by the average surface area to get the total surface area available for photosynthesis.

12. Repeat process on 2 different trees.

13. Tabulate you data.

Analysis:

1. What type of tree has the most photosynthetic surface area, why?

2. How do you think the surface area would differ if we measured a shrub?

3. Why is so much surface area necessary for photosynthesis?

4. What do your measurements tell you about your trees?