Calculating the Mitotic Index of a Growing Root Tip

Produced by Science & Plants for Schools (SAPS), this investigation enables students to investigate the process of mitosis in a growing root tip. The mitotic index is the fraction of cells in a microscope field which contain condensed chromosomes.

In this activity students prepare and stain root tips. Garlic cloves, bought normally for cooking purposes, will produce roots at any time of year. Preparation of the plant materials and the stains is covered in the resource. It is possible to fix the root tips when available and then store them until required.

The investigation is designed for students following a Scottish Highers course but it is equally useful for other post-16 courses in biology.

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This resource is part of Science & Plants for Schools (SAPS): secondary and post-16 resources

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We tried a similar experiment last week with onion roots, but it the stain didn't show the mitosis very clearly. I plan to try out some of the variations in this version to see if we can get a better result.