Required practical 5

• 1. cut 5 mm samples of a root tip using a scalpel
• 2) transfer the root tips to a sample tube containing hcl and leave for five minutes
• 3) transfer the-root tips to a watch glass containing distilled water for five minutes
• 4) dry the root tips on filter paper
• 5) place on a microscopic slide, macerate the root tip with a needle to spread the cells out and make the chromosomes more visible
• 6) as a drop off toludine blue and leave to stain for two minutes
• 7) lower the cover slip onto the slide making sure there are no air bubbles as this may distort the image, gently squash the slide
• 8) place the slide under a microscope and set the objective Len’s to the lowest, use the fine adjustment knob to readjust the focus
• Count the number of cells with visible chromosomes, the are the cells undergoing mitosis
• Mitotic index =number of cells with visible chromosomes/ total number of cells