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Squash Method Onion Root Tip

  • Botany

In this squash method onion root tip post we have briefly explained about onion root tip mitosis stages, principle, requirements, procedure, expected result and applications.

Onion Root Tip Mitosis Stages

For onion root squash, the roots can be easily produced by placing an onion on a water-filled conical flask with the onion disc touching the water, or by placing the onion on wet sand with the bulb partially buried in the sand.

In just two days, about one centimetre long roots emerged, which could then be removed, repaired, and stored. Because the onion plant’s root tip is a fast-growing location, cells divide quickly for viewing onion root tip mitosis stages. The cells are very big, making them easier to see, and the 16 chromosomes stain well.

Allium root tip cells do not undergo synchronised mitosis. Students and Researchers observe onion root tip mitosis stages as well as a variety of intermediate configurations.

Principle

Carmine is a basic dye derived from the Coccus cactus bug. Carmine is combined with glacial acetic acid to make acetocarmine. It’s a DNA-specific stain that’s used to visualise super-coiled chromosomes throughout onion root tip mitosis stages.

Requirements

Materials

1. 1% Acetocarmine solution

2. Onion Root Squash

3. 1 N HCL

4. 1:3 acetomethanol fixatives

5. 45% acetic acid

6. Slide

7. Cover glass

8. Sealing wax.

1% Acetocarmine

Carmine is a natural dye made from the Coccus cactus bug. In 1 L of 45 percent glacial acetic acid, dissolve 10 g carmine, add boileezers, and reflux for 24 hours. Filter and store in dark bottles at 4°C. This solution can be kept indefinitely. By mixing 5 mL of a 10% ferric chloride solution with 100 mL of percent acetocarmine, the staining can be increased.

Procedure

1. Cut the tip of the recently grown root 5 to 8 mm away. The rest of the root should be discarded. Place them on a clean microscope slide and wash them in water.

2. Apply one drop of 1N HCL to the root tip of the slide and 2-3 drops of acetocarmine stain.  Gently warm the slide for one minute over the alcohol lamp. 

3. Using blotting paper, carefully wipe the excess stain. After 10 to 20 seconds, carefully blot one or two drops of water using blotting paper.

4. Apply a drop of water to the root tip once more and cover it with a cover slip to avoid air bubbles.

5. Squash the slide with onion root squash with a hard and uniform pressure with your thumb. (Avoid squeezing the cover slip so hard that it breaks or slides.).

6. Use a compound microscope with a 10x objective to examine onion root tip mitosis stages. Switch to 40X for a better view after scanning and narrowing down to a zone with dividing cells in onion root tip mitosis stages.

Expected Result

Onion Root Squash

Onion Root Tip Mitosis Stages: The plant cells have been visualized using light microscope with the help of Acetocarmine stain.

Further Readings

Reference