Question

give the various steps involved in preparing a temporary mount of onion peel .

Answer 1

Objective:

To prepare a stained temporary mount of an onion peel and to record observations and draw labeled diagrams.

Apparatus and materials required:

An onion, glass slide, watch glass, coverslip, forceps, needles, brush, blade, filter paper, safranin, glycerine, dropper, water, and a compound microscope.

Theory:

Procedure:

1. Take an onion and remove its outermost peel.

2. Now cut a small part from an inner scale leaf with the help of a blade.

3. Separate a thin, transparent peel from the convex surface of the scale leaf with the help of forceps.


4. Keep this peel in a watch glass containing water?

5. Add two drops of safranin stain in the watch glass to stain the peel.

6. Take a clean slide and put a drop of glycerine in the centre of the slide.

7. With the help of a brush and needle transfer the peel on the slide. Glycerine prevents the peel from drying up.

8. Carefully cover it with a coverslip and avoid any air bubble from entering interring the coverslip.

9. Remove any excessive glycerine with a filter paper.

10. Observe the prepared mount of the peel under the low and high magnification of a compound microscope.

Observations:

A large number of rectangular cells are visible. These cells lie close to each other with intercellular spaces between them. These cells are surrounded by distinct cell walls. These cells have a dark stained nucleus and a large vacuole in the centre.