Question

Give the experiment to study plant cells in onion peel​

Answer 1

Answer:

AIM

To prepare stained temporary mount of onion peel cells and to record observations and draw labelled diagrams.

MATERIALS REQUIRED

Onion, plain slides, coverslip, watch glass, needles, forceps, brush, blade, safranin, blotting paper, glycerine and compound microscope.

THEORY

Onion is a multicellular plant. Like other plant cells, the cell of onion peel consists of a cell wall, cell membrane, cytoplasm, a large vacuole and a nucleus. The nucleus lies at the periphery of cytoplasm and vacuole is located in the centre. Presence of large vacuoles and cell wall confirms that cells of onion peel are plant cells.

PROCEDURE

Take a piece of onion and bend it to remove the transparent membranous structure called onion epidermal peel. With help of forcep remove the peel from its inner side.

Place the peel in water in a watch glass.

Add a few drops of stain safranin, to the watch glass containing the peel for staining.

Now, wash the leaf peel with water and transfer it on to a clean slide with the help of brush.

Remove extra water from the slide surrounding the peel with the help of blotting paper.

To this slide, add a drop of glycerine over the peel and place the coverslip in a manner to avoid entry of air bubbles.

Soak away the extra glycerine with blotting paper.

Examine slide under the microscope.

OBSERVATIONS

A large number of rectangular cells with distinct cell wall can be observed.

Cytoplasm is seen as thin layer of deep coloured substance on inner surface of cell wall.

A big central vacuole is present in the cell.

A deeply stained round body called nucleus is seen in each cell.

RESULT

The epidermal peel of onion comprises of rectangular shaped cells. Each cell comprises of a nucleus, a central vacuole, thin layer of cytoplasm and cell wall.

As cell walls and large prominent vacuole are present in each cell, the cells placed under observation are plant cells.

PRECAUTIONS

Always take a clean slide and hold it by its edges to avoid making the slide dirty.

Peel should be properly stain. Avoid under-staining or excessive staining of the peel.

Always transfer the peel with the help of brush.

Mounting of the peel should be done in centre of slide.

Avoid folding of the leaf peel.

Remove extra glycerine with the help of blotting paper.

Avoid entry of air bubbles while placing the cover slip.

Required diagrams are in attachment

Answer 2

Aim: Preparing a stained temporary mount of onion peel cells, recording findings, and creating labelled diagrams.

Materials required: Onion, plain slides, watch glass, needles, coverslip, forceps, blade, brush, blotting paper, safranin, compound microscope, and glycerin.

The color employed for creating a temporary mount of the onion is safranin. In cytology, safranin is widely utilized. Cell nuclei will get stained in crimson.

Procedure:

1. To remove the onion epidermal peel, which is a translucent, membrane-like structure, bend a slice of onion. Using a forceps, remove the peel from the inside of the object.
2. Place the peel in a watch glass with water.
3. Add a few drops of stain safranin to the watch glass containing the peel to make it stained.
4. The leaf peel should now be washed with a brush and moved to a spotless slide.
5. To remove extra water from the slide covering the peel, use blotting paper.
6. This slide should have a drop of glycerin added, and the coverslip should be positioned to prevent air bubbles from entering.
7. Blotting paper should be used to remove any extra glycerin.
8. Utilize a microscope to examine the slide.

Observation:

1. There are several rectangular cells that each have a unique cell wall.
2. On the inside of the cell wall, there is a thin film of a dark-colored substance that is the cytoplasm.
3. A large central vacuole is present in the cell.
4. The nucleus, a spherical body that is heavily pigmented, is present in every cell.

Results:

Rectangular-shaped cells make form the onion epidermal peel.

Each cell has a nucleus, a central vacuole, a thin layer of cytoplasm, and a cell wall.

Hence, The cells being studied are plant cells since they each have cell walls and a sizable, noticeable vacuole - onion peel.

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