AQA A Level Biology复习笔记8.2.4 Producing Tissue Cultures of 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
• This technique is used by scientists to reproduce endangered species of plant

Apparatus

• Disinfectant
• Sterilising solution
• Scalpel
• Gloves
• Forceps
• Cauliflower
• Agar growth medium containing sterilant
• Container

Method

• 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 a fungal growth rather than an explant growth

   

• Break of 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

   

• 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

   

• Take out 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 contains a sterilant to ensure no contamination occurs throughout the experiment

   

• Leave the container holding the agar growth medium and the explant on a sunny windowsill for 3 weeks

Results

• The result of this experiment is to grow a cauliflower clone from an explant
• This shows that the cells in the explant have the capability to produce all the different cell types that make up a full cauliflower plant, hence they are totipotent