Guide to the practical teaching
of biology and genetics

Mitosis in plant cell

TASK 1: Mitóza v buňkách kořínku cibule

NP: onion rootlet stained with acetorcein

Compress an onion rootlet under a cover glass with your finger (compression preparation) and observe the particular mitotic phases.

Staining procedure:

The base of onion is sunk in water to let roots grow. When roots start to grow, their ends (about 2-3 mm) are cut and fixed in acetic acid and 96 % ethanol (in ratio 1:3) for 20 min. Then roots are macerated in hydrochloric acid and ethanol (in ratio 1:1) for 10 min., washed in distilled water for 10 min. and finally stained with acetorcein for 10 min.

Fig.: Mitosis in onion rootlet cells.

TASK 2: Mitotic phases in permanent preparation

PP: onion (and/or bean) rootlet - "kořínek cibule, kořínek bobu"

Observe 30 mitotic figures (cells in mitosis) and determine mitotic phases. Which of them is the most frequent and why?

TASK 3: Defects of mitosis

NP: onion rootlets treated with hydroquinone and stained with acetorcein.

Prepare compression preparation of the onion rootlet and observe defects of mitosis.

Fig.: Defects of mitosis: A – chromosome fragmentation in prophase, B – anaphase bridge, C –defective anaphase in cell with damaged chromosomes.