Aim: To make a temporary slide of eukaryotic cells
Material required: A bulb of onion, watch glass, forceps, brush, needle, slide, cover slip, safranin stain, glycerine, blade and microscope
Procedure:
1. Take a piece of onion bulb and break it to get a transparent membrane peel.
2. Using a blade cut the membrane into a piece of approximately 2 sqmm; discard the remaining parts.
3. Stain this section of membrane with safranin in a watch glass. Use a brush or forceps.
4. Wash this stained part with water to remove the excess stain.
5. Using a brush or forceps, place this section on a clean slide; put some glycerine on it. Place a clean cover slip over it using a needle.
6. Remove the excess glycerine using a blotting paper.
7. Observe the slide under a microscope.
Observation:
1. Several layers of rectangular, compactly packed cells can be seen under the microscope.
2. A cell wall is seen around the cell and a well defined nucleus can be seen inside each cell.
3. Intercellular spaces are not found between the cells.
Precautions:
1. The membrane must be placed in a single layer on the slide; not in double layers.
2. The slide must be neat and clean and without air bubbles.
3. Focus the microscope carefully without allowing the objective lens to touch the cover slip.
