Chapter 17 Tissue Culture: Micropropagation 439
Copyright Goodheart-Willcox Co., Inc.
When plantlets are removed from the in vitro rooting culture of stage 3,
the roots are lightly washed to remove any medium, which could provide
the perfect habitat for bacteria or fungi in a high-humidity environment.
Plantlets are placed in a sterile potting mix that is considered optimal for that
particular plant’s growth. Initially, plantlets are exposed to high amounts of
humidity and very little sunlight.
During the fi rst weeks after transplant, plantlets may be covered with
plastic or humidity domes to increase the amount of moisture. Stage 4 may
require up to several weeks. Just before plants are ready to be transplanted
outdoors or in a greenhouse, they are subjected to drier air and greater
quantities and intensities of light. These conditions help harden the plants for
survival in their new environment, Figure 17-13.
The Future of Tissue Culture and
Micropropagation
Micropropagation is a biotechnology method used in forestry, agronomy,
and horticulture to preserve plant and tree species; create new and improved
fruits, vegetables, and ornamentals; and to expedite the development of some
genetically modifi ed crops. Although there is some controversy regarding the
use of biotechnology techniques in plant production, micropropagation shows
great promise to help producers meet the food and fi ber needs of the world’s
growing population. Some of the benefi ts of micropropagation include:
• Massive replication of plant materials that can be used for benefi cial
production of biopharmaceuticals (plant-derived compounds used to
treat illnesses).
• Use of explants to determine if cells (rather than entire plants) are
sensitive to various chemicals (particularly pesticides).
“Use
plants to
bring
life.”
—Douglas Wilson.
B
smcfeeters/Shutterstock.com
Figure 17-13. A—These plants survived the first three stages of tissue culture and are being acclimated to their new
environment in stage 4. B—This potato plant has been placed into a container with a new potting soil medium.
A
Photography by Agri-Starts, Inc.
Corner Question
What can be done to
improve the growing
conditions while plants
are in vitro?