B Sc III 

To study the cell structure from onion leaf peel

Aim: To study the structure from onion leaf

Requirement: leaves of onion, aqueous safranin, glycerin, forceps, blade, slide, cover slip, microscope etc.

Procedure:

1.   Tear onion leaf diagonally to get a small piece of lower epidermis. Or scratch lower surface of onion leaf.

2.   Cut peeled epidermis in small pieces

3.   Stain these pieces in safranin.

4.   Remove excess of stain by repeated washing in water.

5.   Mount a small piece of each peel in glycerin on separate slides.

6.   Observe these slides under compound microscope.

Observation:

1.The cells of an onion leaf are generally rectangular in shape

2.Size ranges from 250-400 micrometers in length.

3.Microscopic view of an onion peel showing several rectangular cells,

4.Each cell shows a small, spherical nucleus.

5. The cells are eukaryotic.

6.cells appear green in colour

7.Each cell has distinct outermost cell wall which provides shape and protection to the cell.

8.Inside the cell wall there is cell membrane.

9.Cell is filled with cytoplasm inside the membrane.

10.     A nucleus is situated in the cytoplasm  shows large vacuole

11.     Cell has number of discoid chloroplast.

* * * * *

To study the cell structure from Tradescantia leaf

Aim: To study the structure from Tradescantia leaf.

Requirement: leaves of Tradescantia, aqueous safranin, glycerin, forceps, blade, slide, cover slip, microscope etc.

Procedure:

1.   Tear a Tradescantia leaf diagonally to get a small piece of lower epidermis. Or scratch lower surface of onion leaf.

2.   Cut peeled epidermis in small pieces

3.   Stain these pieces in safranin.

4.   Remove excess of stain by repeated washing in water.

5.   Mount a small piece of each peel in glycerin on separate slides.

6.   Observe these slides under compound microscope.

Observation:

1. The cells of an Tradescantia leaf are generally polygonal in shape
2. Size ranges from 400-600 micrometers in length.
3. Microscopic view of Tradescantia peel shows several polygonal cells.
4. Each cell shows a small, spherical nucleus.
5. The cells are eukaryotic.
6. Cells appear pink in colour
7. Each cell has distinct outermost cell wall which provides shape and protection to the cell.
8. Inside the cell wall there is cell membrane.
9. Cell is filled with coloured cytoplasm inside the membrane.
10. A nucleus is situated in the cytoplasm  shows large vacuole
11. Cell has number of discoid chloroplast.

*****