Required practical 2
Mitosis in meristem tissue
Preparation of stained squashes of cells from plant root tips; set up and use of optical
microscope to identify the stages of mitosis in these stained squashes and
calculation of a mitotic index.
Mitosis is a process that is important to multicellular organisms and is used for growth and
repairing and single celled organisms are dependent upon it as it is a primary mean of
asexual reproduction. Mitosis occurs via cell duplication where one cell divides to produce
two genetically identical daughter cells which contain 50% each of a copy of the original
cell's chromosomes. Mitosis occurs in stages: Interphase occurs in between cycles
Prophase is when the chromatin becomes chromosomes and attach to spindle fibres by the
centromeres, the nuclear envelope breaks down. Metaphase is when the chromosomes line
up along the centre. Anaphase, when chromatids are pulled to opposite poles of the cell.
Telophase, when the chromosomes become chromatin and the nuclear envelope reforms,
Mitosis only ends once cytokinesis has occurred.
The aim of this experiment is to use an optical microscope to identify the stages of mitosis in
a preparation of stained, squashed root tip and calculate a mitotic index.
Apparatus
● Beaker
● Scalpel
● Forceps
● Toluidine blue stain
● Root tip
● Hydrochloric acid
● Microscope
● Benchmat
Safety
Hazard Risk Safety Precaution
Hydrochloric acid May cause harm/irritation Wear eye protection;
to eyes or in cuts avoid contact with skin
Toluidine blue O stain May cause harm/irritation Wear eye protection;
to eyes or in cuts avoid contact with skin
Scalpel Cuts from sharp object use forceps to hold
Cut away from fingers sample whilst cutting
Mitosis in meristem tissue
Preparation of stained squashes of cells from plant root tips; set up and use of optical
microscope to identify the stages of mitosis in these stained squashes and
calculation of a mitotic index.
Mitosis is a process that is important to multicellular organisms and is used for growth and
repairing and single celled organisms are dependent upon it as it is a primary mean of
asexual reproduction. Mitosis occurs via cell duplication where one cell divides to produce
two genetically identical daughter cells which contain 50% each of a copy of the original
cell's chromosomes. Mitosis occurs in stages: Interphase occurs in between cycles
Prophase is when the chromatin becomes chromosomes and attach to spindle fibres by the
centromeres, the nuclear envelope breaks down. Metaphase is when the chromosomes line
up along the centre. Anaphase, when chromatids are pulled to opposite poles of the cell.
Telophase, when the chromosomes become chromatin and the nuclear envelope reforms,
Mitosis only ends once cytokinesis has occurred.
The aim of this experiment is to use an optical microscope to identify the stages of mitosis in
a preparation of stained, squashed root tip and calculate a mitotic index.
Apparatus
● Beaker
● Scalpel
● Forceps
● Toluidine blue stain
● Root tip
● Hydrochloric acid
● Microscope
● Benchmat
Safety
Hazard Risk Safety Precaution
Hydrochloric acid May cause harm/irritation Wear eye protection;
to eyes or in cuts avoid contact with skin
Toluidine blue O stain May cause harm/irritation Wear eye protection;
to eyes or in cuts avoid contact with skin
Scalpel Cuts from sharp object use forceps to hold
Cut away from fingers sample whilst cutting
