CP 06 - Prepare and stain a root tip squash to observe the stages of mitosis.

Equipment list

• Root

• Scalpel

• Ruler

• Boiling tube

• Hydrochloric acid

• 25 cm³ measuring cylinder

• Pipette

• Distilled water

• Paper towels

• Microscopic slide

• Cover slip

• Mounted needle

• Stain

• Optical microscope

Method

1. Use a scalpel to measure and cut the end 1 cm of the root.

2. Measure out 10 cm³ of 1 mol/dm³ hydrochloric acid into a boiling tube and place it in a water bath at 60°C.

3. Transfer the root tip section into the boiling tube and leave it for 5 minutes.

4. Remove the tip and use a pipette filled with distilled water to rinse it. Leave it to air dry on a paper towel.

5. Now cut the end 5mm of the root tip and place this on a microscopic slide. Use a mounted needle to spread the specimen out forming a thin layer that will allow light to pass through when observing it under a light microscope.

6. Use a pipette to apply a couple drops of stain to the specimen, the stain binds to chromosomes making them easier to see, use Toluidine Blue O or Feulgen Stain.

7. Finally, place a cover slip on top of the specimen on the microscopic slide. Press down firmly , further spreading and thinning viewed under an optical microscope.

Mitotic Index

Cells undergoing mitosis/total cells

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