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To prepare a temporary mount of a leaf peel to show stomata - Science Practicals

Aim
To prepare a temporary mount of a leaf peel to show stomata.

Theory
Stomata mean ‘mouth’ which are pore found in the epidermis of leaves, stems and all other plant parts found above the ground. Stomata permit the exchange of gases between the atmosphere and the inside of the leaf.
Materials Required
Lily leaf, Watch glass, Slide, Cover slip, Safranin solution, Glycerine, Forceps, Dropper, Scissors or Blade, Petri Dish, Filter Paper, Distilled water, Brush, Compound microscope

Procedure
Step 1: A lily leaf is taken and simply fold in the centre which gets broken into two pieces.
Step 2: One leaf piece is gently pulled and we got a transparent leaf peel.
Step 3: The leaf peel of lower epidermis is taken and cut with scissors or a blade into small pieces. These pieces transferred with the help of paintbrush into a petri dish containing water. (Do not keep them without water. They will dry)
Step 4: A piece of leaf peel is selected and transferred into another watch glass containing dilute solution of safranin (a red stain).
Step 5: With the help of paintbrush specimen is transferred back into first water containing petridish/watch glass to remove excess of stain.
Step 6: Specimen is transferred to slide with the help of brush.
Step 7: A drop of glycerine is put on the peel and it is covered carefully with a cover slip by using needle to avoid air bubbles. Excess glycerine is removed with help of a filter paper.
Step 8: The leaf peel is observed under low power of microscope.
Step 9: For inner details, again the leaf peel is observed under high power (45x) of microscope.

Observation
1. A horizontal row of cells is seen.
2. The cells may be irregular or rectangular in shape, depending upon the leaf used for leaf peeling.
3. At certain places stomata are seen.
4. Each stoma is guarded by a pair of bean shaped cells that are guard cells.
5. The central pores/apertures are called stomata.
6. Inner wall of guard cell is thicker than the outer wall.

Precautions
1. The epidermal peel should be taken from a freshly-plucked leaf.
2. Take the epidermal layer from the lower surface of a leaf, as it has more stomata.
3. Always use a clean glass slide.

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