So
What is Tissue Culture?
Tissue culture is when a piece of plant is put into the tiniest of
greenhouses...a test tube....and a miracle takes place. If the test tube is
free of micro-organisms and the media in the test tube has the correct
balance of chemicals and growth hormones, that little piece of plant will
reproduce replicas or clones of the single parent plant. That little piece
of plant material can replicate in incredible numbers so theoretically, one
small piece can produce an infinite number of clones.
From these humble beginnings,
theoretically infinite numbers can be
produced from tissue culture samples.
What is the process?
Plants are first initiated, which means they are surface sterilized and
small buds or growing tips are placed on media which has the right amount of
fertilizer, vitamins and growth regulators. This "soup" is solidified by
agar - something like Jell-O so that the plants can stand up straight and
have nutrients diffuse to the plant and also have toxins diffuse away from
the plant. Growth regulators incorporated into the media such as BAP, TDZ ,
Auxins such as IBA, IAA determine what the plant does. Once, clean in
culture, the plant is multiplied which means that roughly every 2 to 3
weeks, the plant material is removed from the jar or test-tube, divided and
trimmed as required and put back onto fresh media. This work is done in a
laminar flow through hood. The hood uses hepa filters which clean to point
two microns. The plants are placed on paper towel which have been sterilized
in an autoclave. Work is very fussy and a sterile technique has to be
learned. When the required numbers of plants have been grown, the media is
changed and often, but not always, the plants are put onto Elongation media
so that good micro cuttings can be harvested. The final stage is rooting and
again, that can be done in the lab using a different media or a greenhouse
employing a sophisticated propagation greenhouse. The cuttings are rootless
and very perishable at this stage and require a great deal of attention.
So what is a clone and what is the
offspring of a seed?
Seeds are the result of sexual reproduction and each seed has its own
genetic make up unique from other seeds and unique from either parent
plant. Tissue cultured plants are micro propagated cuttings or clones,
genetically identical to the mother and all the daughter plants. |
Why is tissue culture used?
Tissue culture is used for many reasons but the 3 major reasons DnA
Gardens are concerned with are 1) Large quantities of plant production for
the sake of volume, 2) to speed up the production of new varieties into
the market place. Large amounts of plants can be produced in a very short
time compared to conventional propagation methods, 3) to establish and
maintain virus free stock as in the case of the seed potato industry.
Working in a tissue culture lab is like working in a hospital operating
room. Sanitation is imperative. If the plant cultures become infected with
fungus or bacteria, the contaminants soon over take and kill the cultures.
Other applications include protoplast fusion and the induction and
selection of mutants and the biosynthesis of plant metabolites. The end
result, lovely, clean plants.
DNA Tissue
Lab
Regulating Environmental Factors
Separating Tissue Samples
Dispensing Media |
