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Study Stomata
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A microscope exercise by Donald Cronkite and Jewel Reuter |
| Leaves are especially adapted for absorbing light and
regulating gas exchange. The Tangerine Section Model of Guard Cells: Tangerine sections are excellent models of guard cells. When the guard cells are swollen the stoma is open and when the guard cells are limp or flaccid the stoma is closed. Soak tangerine sections in a saturated salt solution for a few hours. Place two flaccid sections on the overhead projector and two turgid sections (unsoaked) on the overhead projector to form open and closed stomata. You can compare the model to Wandering Jew guard cells observed directly under the microscope. |
Real Guard Cells and Stomata Without Preparation:
The Tradescantia of
choice for this study
has purple leaves, and the guard cells are green. Place the leaf on
the stage of the microscope. No preparation is need. Focus and you
will see the guard cells. To compare open and closed stomata, place some
leaves in the dark and some leaves in the light for 24 hours. Then compare
the stomata. The leaves in the light will have open stomata and the ones
fro the dark will have closed stomata.
Students can design various lab to test the factors that influence
the guard cells.
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Donald Cronkite,Hope College, Holland, MI 49423
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