2.6.3 Indentifying Mitosis In Plant Cells

Question 1

Identifying Mitosis in Plant Cells

Answer 1

Growth in plants occurs in specific regions called meristems
The root tip meristem can be used to study mitosis
The root tip meristem can be found just behind the protective root cap
In the root tip meristem, there is a zone of cell division undergoing mitosis
Pre-pared slides of root tips can be studied or temporary slides can be prepared using the squash technique

Question 2

Squash Technique Method

Answer 2

Garlic or opinion (Allium cepa) root tips are mot commonly used
- the bulbs can be encouraged to grow roots by suspending them over water for a week or two
Remove the tips of the roots (about 1 cm) and place in a suitable stain
- e.g. warm, acidified acetic orcein, which stains chromosomes a deep purple
The stained root tip is gently squashed on a glass slide using a blunt instrument
- e.g. the handle of a mounting needle
Cells undergoing mitosis can be seen and drawn
Annotations can then be added to these drawings to show the different stages of mitosis

Question 3

Limitations

Answer 3

It can be very difficult to distinguish between prophase and telophase in cells
- looking at the number of nuclei within one cell can help to identify which stage is likely to be occurring
- if there are multiple nuclei within one cell then telophase is occurring
The size of cells or structures of tissues may appear inconsistent in different specimen slides
Optical microscopes do not have the same magnification power as other types of microscopes and so there are some structures that cannot be seen
The treatment of specimens when preparing slides could alter the structure of cells