Plant research often involves growing new plants in a controlled environment.
These may be plants that we have genetically altered in some way or may be
plants of which we need many copies all exactly alike. These things can be
accomplished through tissue culture of small tissue pieces from the plant of
interest. These small pieces may come from a single mother plant or they may
be the result of genetic transformation of single plant cells which are then
encouraged to grow and to ultimately develop into a whole plant. Tissue
culture techniques are often used for commercial production of plants as well
as for plant research.
Tissue culture involves the use of small pieces of plant tissue (explants) which
are cultured in a nutrient medium under sterile conditions. Using the
appropriate growing conditions for each explant type, plants can be induced to
rapidly produce new shoots, and, with the addition of suitable hormones new
roots. These plantlets can also be divided, usually at the shoot stage, to
produce large numbers of new plantlets. The new plants can then be placed in
soil and grown in the normal manner.
Many types of plants are suitable for use. Cauliflower, rose
cuttings, African violet leaves and carnation stems will all easily produce clones
(exact genetic copies) through tissue culture. Cauliflower florets in particular
give excellent results since they can be grown into a complete plant in the
basic tissue culture media, without the need for additional growth or root
hormones. Green shoots are generally observable within three weeks, and
roots develop within six weeks.
The most important part, however, is to maintain as sterile an
environment as possible. Even one fungal spore or bacterial cell that comes
into contact with the growth media will rapidly reproduce and soon completely
overwhelm the small plant piece that you are trying to clone.