RP02: Calculating Mitotic Index Using Plant Cells

Question 1

Where in plants can cells undergoing mitosis be found

Answer 1

Meristem tissue at shoot and root tips

Question 2

What is mitotic index

Answer 2

Ratio of cells undergoing mitosis to total number of cells in a sample

Question 3

Outline procedure to repeat a root tip slide

Answer 3

1. Warm 1M HCl to 60*C in water bath
2. Cut root tip using a scalpel and add to HCl. Leave for 5 mins
3. Remove from HCl and wash with distilled water
4. Cut tip of root tip sample and place on a slide
5. Add a few drops of stain to make chromosomes visible

Question 4

State formula for mitotic index

Answer 4

Mitotic index =

Number of cells with visible chromosomes
————————————————————
Number of cells in sample

Question 5

State hazards and precautions for reagents used in this procedure

Answer 5

HCl - corrosive, avoid contact with skin, wear eye protection

Toluidine blue O stain - irritant, avoid contact with skin, wear eye protection

Scalpel - cut away from fingers