ALCA Members PLC Domains Data Standards Map Plan Curriculum Assessment Strategies

Making Your Own Onion Root Tip Slides

Have you ever wished that you could have your students do a lab exercise, but there was very little money to buy the ever rising cost of slides? This tool will allow your students to make their own onion root tips slides for use in the study of mitosis. Not only will this tool cut down on expense, but it will give the students a sense of accomplishment.

Learner Goals

    1. Root tips From the green onions provided, cut one or two onion roots 1cm long.
    2. HCl Place the root(s) on a slide and lyse them by adding 1 drop of HCl on top of the roots.
    3. Steam Heat the slide over a flame until it steams. This will be approximately 30 seconds. Do not allow the roots to dry out. You may need to add more HCl. You will need to pass the slide back and forth. If the slide were to remain in the flame, it could shatter.
    4. Blot Remove the slide from the flame and blot off the acid.
    5. Methylene blue Add one drop of methylene blue on top of the roots.
    6. Steam again Steam the slide over the flame for 30 seconds.
    7. Observe Blot. Add one drop of methylene blue. Add a coverslip, smash gently with a pencil eraser to flatten, and then observe. (If the stain is too dark, add a drop of water to one side and draw the water through by placing a paper towel at the opposite end.)

Required Resources

  • Equipment
  • goggles
  • 1M hydrogen chloride (HCl)
  • Bunsen burner or alcohol lamp
  • methylene blue
  • fresh green onions with roots
  • pencil with eraser
  • paper towels
  • slide
  • cover slip

Optional Resources

  • Checkllists (Rubrics) This rubric may be used as a student/teacher checklist and/or a teacher evaluation tool. It is based on a point grading system. To calculate a percentage grade, divide the total points earned by the total points possible. Total Points Possible: 27 ists (Rubrics)

Learner Notes

  • Be certain to cut and use the root tip.

Please enter a Registration Key to continue.