root tip practical

• Mitosis root tip squash


  A required practical where students prepare a stained squash of cells and work out the mitotic index
• Preparing the slide


  1. Cut off last 5mm of root tip

  2. Add to hydrochloric acid in water bath at 60°C for 10 minutes

  3. Rinse in distilled water

  4. Transfer to slide

  5. Add 2 drops of acetic orcein stain

  6. Carefully lower cover slip

  7. Leave for 10 minutes

  8. Gently squash
• Mitotic index


  Percentage of cells currently undergoing mitosis
• Mitotic index = Number of cells in mitosis / Total number of cells x 100