Root Tip Squash (AS Biology Unit 2 Topic 3 Edexcel)

Root Tip Preparation

Cut 1cm of a root tip of a growing plant (e.g. onion)
=> this is because the root tips are the area where unspecialised cells are going through mitosis, which is what we want to observe
Place 2cm(3) of HCl into a 60ºC waterbath until it reaches the temperature
Place into a testube of 2cm(3) of HCl for 5 minutes
=> this breaks down the middle lamella between the plant cells
=> allows more of the stain to be absorbed making observation of the cells easier
Remove and place into cold distilled water for 5 minutes

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Place root tip onto a microscope slide
=> this is used to observe the root tip on
Using a glass rod, smooth out, or "squash", the root tip cell
=> too thick will make it hard to differenciate cells above and below
=> too thin may cause it to break
Put a drop of a dye, e.g. acetic orecin on the root tip and leave for 2 minutes
=> this is to allow time for the dye to run through the cells
Place cover slide on top of the root tip and, using filter paper, blot any excess dye that runs from the cover slide
When observing under the microscope you should be able to view the different stages of mitosis

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