To Study Plant Cell From Onion Scale Leaf. | Grade Xi
Rohan Koirala - Wed Dec 27 2023
0APPARATUS REQUIRED:
- Compound microscope
- Glass slides
- Cover slips
- Forceps
- Needle
- Onion bulb
- Glycerin
- Methylene blue
CHEMICAL REQUIRED:
- Methylene blue
THEORY:
Plant cells are eukaryotic cells, meaning they have a true nucleus and other membrane-bound organelles. The onion scale leaf is a thin, transparent layer of cells that can be easily observed under a microscope. When stained with methylene blue, the cell walls and nuclei become visible.
PROCESS:
- Peel off a thin layer of the onion scale leaf using forceps.
- Place the leaf on a glass slide.
- Add a drop of methylene blue to the leaf.
- Cover the leaf with a cover slip.
- Observe the leaf under a microscope using the 40x objective lens.
OBSERVATIONS:
- The onion scale leaf cells are rectangular in shape.
- The cell walls are thin and transparent.
- The nuclei are large and oval-shaped.
- The cytoplasm is filled with small organelles, such as chloroplasts and mitochondria.
OBSERVATION TABLE:
| FEATURE | OBSERVATION |
|---|---|
| Cell shape | Rectangular |
| Cell walls | Thin and transparent |
| Nuclei | Large and oval-shaped |
| Cytoplasm | Filled with small organelles |
CALCULATION:
The average length and width of an onion scale leaf cell can be calculated using a microscope with a calibrated eyepiece.
- Measure the length and width of 10 cells.
- Add the measurements together and divide by 10 to get the average length and width.
RESULTS:
The average length of an onion scale leaf cell is approximately 100 micrometers. The average width of an onion scale leaf cell is approximately 50 micrometers.
PRECAUTIONS:
- Handle the onion bulb and leaf carefully to avoid damaging the cells.
- Do not use too much methylene blue, as this can make the cells difficult to see.
- Be careful not to press down on the cover slip too hard, as this can crush the cells.