Lesson Plan

• Identify the position of xylem and phloem in transverse sections of roots, stems, and leaves.
• Describe microscopic features that distinguish xylem cells from phloem cells.
• Apply correct slide‑preparation and IKI‑staining techniques to observe vascular tissues.
• Compare the arrangement of vascular bundles across different plant organs.

• Light microscopes (×40–×400)
• Prepared slides of root, stem, and leaf sections
• Hand microtome or sharp razor blades
• Iodine‑potassium iodide (IKI) stain and dropper
• Slides, cover slips, lens paper
• Worksheets with labelled diagrams
• Projector for displaying images

Show a vivid image of a plant cross‑section and ask students where water and nutrients travel. Review prior knowledge of transport tissues and the functions of xylem and phloem. Explain that today they will prepare their own slides, stain them, and use a microscope to locate each tissue, aiming to correctly label xylem and phloem in three organs.

1. Do‑now (5'): Students label a blank diagram of a root cross‑section with xylem and phloem positions.
2. Mini‑lecture (10'): Review key microscopic features and staining principles using the projector.
3. Practical preparation (15'): In pairs, collect fresh samples, cut thin transverse sections with a microtome, place on slides, add IKI stain, and cover with a slip.
4. Microscopy observation (20'): Locate the vascular region at low power, then switch to higher power to identify xylem vs. phloem; record sketches.
5. Guided comparison (10'): Complete a table comparing organ, xylem position, phloem position, and typical cell types.
6. Check for understanding (5'): Teacher asks targeted questions; students correct common mistakes.
7. Consolidation (5'): Students finish a worksheet with labelled diagrams.

Recap how xylem consistently occupies the central position while phloem lies toward the periphery across roots, stems, and leaves, reinforcing their transport roles. Students submit an exit ticket describing one distinguishing microscopic feature of each tissue. For homework, ask them to research how xylem and phloem function in water and sugar movement within the plant.