Background information about leaf anatomy for both monocots and dicots.
Explain how the structure of a plant leaf allows the organism to adapt to the level of water typically available in the habitate characteristic for that species.
Text of Learning Exercise:
The tissue organization of angiosperm leaves differs from that of gymnosperms. In addition, the dicot and monocot leaf organization of the angiosperms differ from each other.
Leaf morphology also correlates to the amount of water in the plants habitat. the three genreal morphologies are the hydromorph leaf found on plants adapted to abundant water, xerophytic leaves adapted to a limited water supply, and mesophytic leaves adapted to habitiats intermediate between hydrophytic and xerophytic.
Follow the navigation links for the leaves listed below and then fill in the table.
Go to: http://www.wisc.edu/botany/virtual.html Click on: Links to Image Sets Click on: General Botany
For an examination of a Nerium leaf:
Click on: Leaf Click on: Nerium leaf cross sec Click on: 400 X MC.jpg Click on: cross section MC.jpg
For examination of a Nyphea leaf:
Click on: Leaf Click on: Nymphea leaf cross section Click on: 40X MC.jpg
For an examination of a Pine leaf:
Click on: Leaf Click on: Pine Leaf Click on: Cross section MC.jpg
For an examination of a Syringa leaf:
Click on: Leaf Click on: Syringa leaf Click on: cross section Click on: cross section MC.jpg
For an examination of a Zea leaf:
Click on: Leaf Click on: Zea cross section Click on: 100X MC.jgp
Create a table with five columns and six rows. Column 1: Leaf Name Column 2: Classify leaf as monocot,
dicot or gymnosperm Column 3: list the morphological reasons for your classification Column 4: Is the leaf hydrophytic, xerophytic or mesophytic? Column 5: List the morphological reasons for your water-level classification.
Plant leaves to include are: Nerium, Nymphea, Pine, Syringa and Zea.
Answer the following questions:
1. Why would each of the following leaf morphological features benefit a xeromorphic plant?
a. The presence of trichomes on the leaf epidermis: b. Sunken stomatal crypts: c. Multiple epidermis with thick cutical:
2. Stomata are normally located on the undersides of leaves. Explain why this would benefit the plant?
3. Explain why it would not be beneficial for hydromorphic leaves to have stomata on the lower epidermis that comes into contact with the water.
4. Considering your answer to question 2 above, why can monocot grass leaves have stomata on both the upper and lower leaf epidermis?