Tissue Culture Lab
What Is Tissue Culture?
Tissue culture is a method of plant propagation done in a laboratory. There are many methods of plant propagation including using seeds, cuttings and division.
Plant tissue culture involves growing plants in an artificial medium under sterile conditions in a jar, flask or test tube. In theory, this process can go on indefinitely, producing many plants over time. Some plant tissue cultures are started from very small sections of plant tissue. The plants produced this way are exact copies, or clones, of one another. While cloning is important for producing multiples (hundreds, thousands, even millions) of an individual, tissue culture offers other ways to propagate plants that are not "clones." Some plant tissue cultures are started from seeds. When seeds are used for tissue culture, each new plant is genetically different from its parent plant. Many of the orchids grown in the lab are started from seed. Tissue culture is commonly called "cloning" and "micropropagation."
Why Tissue Culture?
The plant tissue culture lab allows Garden staff to research new methods of reproducing rare plants and using this information to further plant conservation efforts.
Many plant species are threatened because people illegally take plants out of the wild to sell. Commercial laboratories can use the results of our research to produce thousands of plants for retail, thereby lightening the pressure on natural, wild plant populations. With tissue culture, a large number of plants can be produced in a short amount of time compared with traditional methods of planting seeds, cuttings or divisions. Many of everyday plants ware produced from tissue culture, especially tropical houseplants. Tissue cultures started from seeds are sometimes easier and faster than conventional cloning and offer the additional benefit of increased genetic diversity.
How to Do Tissue Culture
Flasks of nutrient medium are first sterilized under high heat and pressure to kill any fungal or bacterial contaminants. The medium in the containers is made of sugars, inorganic salts, plant hormones and a gelling agent (like agar).
The plant material used to start a culture is called an explant and must be disinfected before being placed on a sterile medium. To maintain the sterility of the plant cultures, the containers are opened only in a laminar flow hood, which contains a high-efficiency particle absorption (HEPA) filter. This creates an environment free of airborne organisms that could contaminate the tissue culture. The container of nutrient medium is first sterilized under high heat and pressure to kill any fungal or bacterial contaminants. After the culture has been started, it is stored under lights and carefully monitored for contamination. After a period of days or up to several months, the explants will show signs of growth. Leaves, roots and other organs will begin to develop.
In time, under the proper conditions, the cultures will grow and multiply. They can be divided or subcultured into new flasks as the nutrients in the medium eventually run out. This process can go on indefinitely, producing many plants over time. Plants grown in the laboratory can be transferred to soil conditions carefully by selecting the correct soil mix and gradually lowering the humidity level.
Tissue Culture Benefits
The Garden works to find new ways of propagating native plants like native orchids and trillium. As our research develops, we share our results with the nursery industry. When nurseries are able to get large numbers of native plants from commercial tissue culture labs, they are less likely to sell plants that have been taken out of the wild.
Some of the rare plants that are grown in the tissue culture lab will be replanted in their native habitats. Others are made available to institutions like nurseries, universities and other botanical gardens for research.
Plants grown in this laboratory will be used in endangered species recovery work. One of the main focuses in this lab is the germination, growth and multiplication of native terrestrial orchid species such as the monkey face orchid (Platanthera integrilabia) and the Kentucky ladyslipper orchid (Cypripedium kentuckiense). Tropical orchid species are also grown in the lab for use in Garden displays, for exchange with other institutions, and for recovery work in countries such as Ecuador.
What Can You Do?
- Ask where the native plants you buy come from?
- Are they collected or propagated?
- Never buy plants taken from the wild.
- Support the Garden and other organizations that research and protect endangered plants.