Producing Tissue Cultures of Explants (AQA A Level Biology): Revision Note

Producing tissue cultures from cauliflower explants

• Creating clones of cauliflowers is used to demonstrate totipotency through the production of tissue culture

  • Cauliflower is used because it is comprised mostly of actively dividing cells and can withstand being handled

• Many plant cells are totipotent, unlike animal cells, and therefore, an entire plant can be reproduced from any of these cells

• A small piece of the plant is cut, this is called an explant, which is then grown into a new clone of the original plant

• The technique of using an explant is used by scientists to reproduce endangered species of plants

Apparatus

• Disinfectant

• Sterilising solution

• Scalpel

• Gloves

• Forceps

• Cauliflower

• Agar growth medium containing a sterilant

• Container

Method

1. Wipe all surfaces with disinfectant and soak all apparatus in sterilant

   • It is important to ensure a sterile environment so that no fungi contaminate the experiment, which would result in seeing fungal growth rather than an explant growth

2. Break off a small floret of cauliflower from the plant, then using a scalpel, cut a thin section of the floret (about 1cm long)

   • This thin section is the explant

3. Sterilise the explant by soaking it in sterilising solution for 15 minutes, swirling the explant around within the solution every couple of minutes

   • This ensures that the explant is sterile and therefore only cauliflower cells are present

4. Remove the explant using sterilised forceps and add it to a container of agar growth medium

   • The growth medium contains all the nutrients that the plant needs for growth, and also a sterilant to ensure no contamination occurs throughout the experiment

5. Leave the container holding the agar growth medium and the explant on a sunny windowsill for three weeks

Results

• The result of this experiment is to grow a cauliflower clone from an explant

• This shows that the cells in the explant can produce all the different cell types that make up a full cauliflower plant, hence they are totipotent