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MERLOT II


    

Learning Exercise


Material: Virtual Foliage
Submitted by: Thomas Lonergan on Apr 11, 2001
Date Last Modified: Apr 11, 2001
Title: Leaf Morphology And Adaptations To The Environment
Description: Students will use images of leaf anatomy and classify a series of plants according to the water level the plants require for survival and whether the plant is a dicot, moncot or gymnosperm.
Type of Task: Individual, Student-centered, Supplemental activity, Unsupervised
Time Required 30 to 45 minutes
Topics: Leaf anatomy, ecology
Course: Introductory Biology and General Botany
Audience: College General Ed
Categories:
Prerequisites Skills: Background information about leaf anatomy for both monocots and dicots.
Learning Objectives: 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.
Technical Notes: None
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?
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