Did you ever have a plant that was so unique or so beautiful that you wished you had hundreds or thousands of them to enjoy or to sell? Plant tissue culture (micropropagation) is a technique which will do just that for us. We are going to discuss this tool which is used so extensively in the nursery business and in plant biotechnology. It is a fascinating and useful tool which allows the rapid production of many genetically identical plants using relatively small amounts of space, supplies and time.
Basically the technique consists of taking a piece of a plant (such as a stem tip, node, meristem, embryo, or even a seed) and placing it in a sterile, (usually gel-based) nutrient medium where it multiplies. The formulation of the growth medium is changed depending upon whether you are trying to get the plant to produce undifferentiated callus tissue, multiply the number of plantlets, grow roots, or multiply embryos for "artificial seed".
For many who become superficially aware of the technique it seems shrouded in mystery and is shrugged off as too technical to be of concern. Actually, it is no more of a mystery than taking a cutting of your favorite house plant and growing it to share with a friend. As for being technical, you can begin plant tissue culture with as little as a cookbook approach and a feeling for sterile technique.
Some people have visions of scientists doing plant tissue cultures in white gowns and masks in hospital-clean environments. Such conditions are excessive. While it is true that mold spores, bacteria, and other contaminants will grow and overrun a culture, air that is not moving has a minimum of contaminants. In addition, disinfection of implements, work surface and nearby areas helps eliminate contaminants.
The guidelines for preparation and the laboratory protocol provided here are given as a place to begin. Included with is a limited discussion of some of the many options you have as you explore micropropagation. We can discuss these in more depth if you have questions, concerns or related experiences to share. I would be particularly interested in success and challenges you may have had or are currently having in your classroom.
Some suggestions are given for the following
(a) Selecting plant sources. Some species, or even clones are easier to grow in culture than others. Some respond reluctantly to culture, some do not respond at all, and many plants have never been tried.
(b) Choosing a growth medium (price, convenience, type of plant and purpose of the micropropagation all enter into this decision.) How important are the kinds of hormones used? On limited scale, media ingredients are available at the grocery and health food stores.
(c) Suggestions for media preparation and sterilization. There are alternatives to sterilization in a pressure cooker or an autoclave.
(d) Methods for cleaning, storing and manipulating explants (plant pieces to be cultured).
Given certain basics there are many options for procedure, equipment and supplies for plant tissue culture. Some of your decisions will be based upon the amount of time, money and space you have. Other decisions will be based upon why you are doing plant tissue culture and what you expect as a result (more plants?) . Catalogs, such as Sigma, Carolina Biological, or Edmund Scientific are good reference and they are for purchasing needed materials..
I look forward to sharing tissue culture experiences with you.
References:
Debergh, P.C. and R.H. Zimmerman, eds. 1991. Micropropagation, Technology and Application. Kluwer Academic Publishers. $61.50. Lab design, info on labs worldwide, in depth discussions of problems. Not for the beginner.
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