Teaching science: Onion and Garlic, how Mitosis works;

Mitosis is that part of the cell cycle in which the nucleus divides into daughter cells. Every daughter cell has the same number of chromosomes as the parent nucleus.

“Where a cell arises, there must be a previous cell, just as animals can only arise from animals and plants from plants.” (Rudolf Virchow in 1858)

Mitosis

( http://www.free-anatomy-quiz.com/mitosis.html)

Protocol for visualizing mitosis:

Toluidine blue has high affinity for acidic tissue such as DNA`s and RNA`s and is commonly used for staining.

Procedure:

1.) Use garlic or onion and insert sticks to prevent that the sample drowns in the beaker filled with water; the root area should be covered.

2.) After three days the roots should be sufficiently long (the longest roots possess a higher efficiency of mitosis)

3.) Transfer the roots into a beaker with 1 M hydrochlorid acid

4.) Heat at 60 degree for around 6 min

5.) Remove the root tips, wash several times with water, dry with Kimwipe

6.) Chop the tips and separate the fragments (Slice it with a razor blade)

7.) Add one drop of 0.5% Toluidine blue on your preparation for 2 min

8.) Wash with water and dry

9.) Shorten the roots to around 2 mm (neither the top end of the root tips nor the upper portion should be used; they are mitosis inactive). Cut in between; in this way you will obtain the sweet spot where the roots are most active in mitosis

10.) Search for cells that show different stages of staining

(http://www.funsci.com/fun3_en/mitosis/garlic.htm)

I apologize, but we have not a camera attached to our microscope; thus, I use a typical result.

Tips: The experiment will need sufficient time, as the students have to learn to separate the fragments and obtain a good microscope sample.