Prepare and examine the transverse section of a dicotyledonous stem (LC 2026) (Leaving Cert Biology): Revision Notes

Prepare and examine the transverse section of a dicotyledonous stem

Materials needed:

• Celery stem
• Blade
• Petri dish
• Water
• Microscope slide
• Iodine solution
• Coverslip
• Microscope

Method:

1. Cut several short lengths of celery stem using a blade. Cut at the node, at right angles to the stem, and away from the body to get a very thin transverse section.
2. Place the cut sections in a petri dish of water to prevent drying out.
3. Remove the thinnest section from the water and place it on a microscope slide in a drop of water.
4. Add drop of iodine solution to highlight vascular tissue (vascular bundles).
5. Add a coverslip. Lower slowly at an angle of 45°.
6. Examine the section under the microscope.
7. Draw labelled diagrams of your observations.

Results:

In a dicot stem, vascular bundles are arranged in a ring.