Prepare A Temporary Mount of the Onion Root Tip To Study Mitosis

Aim

To study mitosis by preparing a temporary mount of an onion root tip.

Necessary Materials & Apparatus

  • Onion
  • Watch glass
  • Glass slide
  • Filter paper
  • Aceto-alcohol
  • Coverslip
  • Water
  • N/10 Hydrochloric acid
  • Acetocarmine Stain
  • Burner
  • Forceps
  • Dropper
  • Blade
  • Needle
  • Compound microscope

Procedure

  • Place the onion on a tile
  • Using the blade, remove the dry roots
  • Regrow the root tips by placing the bulbs in a water-filled beaker
  • After 3 to 6 days, new roots may emerge
  • Slide 2 to 3 cm off freshly grown roots and place them on a watch glass
  • Use a forceps to transfer the freshly cut tips to a test tube containing Aceto-alcohol (1:3 = anhydrous acetic acid: ethanol)
  • Submerge the root tips in the solution for 24 hours
  • Use the forceps to take out a single root and place it on a glass slide.
  • Put a single drop of N/10 HCl on the root tip
  • Then, put 2-3 drops of acetocarmine stain
  • Use a burner to warm it, and ensure that the stain does not dry up.
  • Use a filter paper to blot out the excess stain, if any
  • Cut the significantly stained portion of the root using a blade and place it on a slide. Discard the rest of the root
  • Put a drop of water on the root tip
  • Place a coverslip using a needle
  • Tap the coverslip such that the meristematic tissue of the root tip is compressed and spread out as a thin layer.
  • The preparation is ready for studying mitosis.

Observation

Use the compound microscope to study the various phases of mitosis.

1 Comment

  1. Very helpful and easy to understand

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