Botanic Gardens Trust, Sydney, Australia

Tissue culture, cloning & seedbanks

What is tissue culture?

  • Click here to find out about the techniques involved and some of the applications to which tissue culture can be applied.
  • The key to tissue culture is 'totipotency' - which means the ability for a plant to regenerate from a single cell back into a whole plant.
  • Tissue culture is a form of cloning in which the plants are all genetically the same - similar to taking cuttings.
  • Tissue culture is used to mass produce plants.
  • Tissue culture must be done in a sterile environment - plants are grown without roots on a growth medium that supplies all the nutrients they require.
  • The growing media can be changed to suit different plant species but includes water, vitamins & minerals and a gelling agent like agar.
  • Plant growth regulators (plant hormones) like auxins and cytokinins are added to increase multiplication of the plants, or auxins for developing roots.
  • Plants are grown in plastic or glass containers placed in controlled growth rooms set at about 24 degrees Celsius, under lights (16 hours on and 8 off).

What is cloning?

  • Click here for a definition of cloning.
  • A clone can be a simple as taking a plant cutting from your mother’s favourite rose, i.e. the cutting is now an identical copy of the parent from which it came. 
  • You would be surprised many things you eat, use and wear are from clones.
  • An example of a clone inculdes Granny Smith apples - a whole orchard contains trees that are clones from the original parent.
  • Forestry trees - many are clones so that they provide good wood quality and high yields.
  •  Wollemi Pine - a plant thought extinct and only known previously from fossil records has been saved through cloning. All the plants currently for sale around the world are clones of the original trees found in the wild.
  • Tissue culture and cuttings are forms of cloning as they produce identical plants from a single source.
  • Cloning has been used for plant species for a long time.
  • The principles are the same for native and non native species.
  • Reasons for cloning include the maintenance of ‘special’ or ‘superior’ qualities of individual plants e.g. particular flower colour (African violets), flowering time, named varieties (roses, camellias, grevilleas), fruiting times (apples, oranges). Generally plants grown from seed show variability.
  • Cloning can produce flowering/fruiting plants more rapidly than growing plants from seed.

Seedbanks

  • The NSW Seedbank is located at the Australian Botanic Garden, Mount Annan.
  • Seedbanks allow long term storage of plant parts.
  • Seedbanks allow storage of large numbers of seeds in a small amount of space.
  • Seedbanks increase the gene pool available for using plants in the future (e.g. heritage vegetables are making a comeback).
  • Seeds are a cost-effective way of disseminating plant material around the world.
  • Seedbanks provide material for research and plant breeding (e.g. to develop new varieties or disease resistance).
  • Seed storage is easy for most species, therefore quite achievable.
  • Seedbanking is rather like an insurance policy in case of disaster.
  • Seeds are safer to transport around the world if you want to minimise the introduction of pests and diseases usually associated with living plants. 

Tissue culture
Jar containing tissue cultured Flannel flowers growing in a sterile environment

Tissue culture
Tissue culture is carried out in a sterile environment using sterile equipment

Tissue culture
New material is surface sterilised and small sections placed into test tubes containing agar media

Tissue culture
Once the material has grown it is removed in a sterile environment

Tissue culture
Here it is cut into smaller sections or 'multiplied'

Tissue culture
Large amounts of clonal material can be produced this way