African Violet Background Information:
The African Violet or Saintpaulia ionantha was first discovered in Tanzania and Eastern Africa and it wasn’t introduced into the United States until 1894 (1). Since then, it has become one of the most popular house plants because of the fact that it survives well in most indoor home conditions in very little light (2).
The process of tissue culture is used to grow certain tissue separate from the organism that it came from. In the case of plants, a special media is used based upon what tissue you are planning to propagate. Depending on the plant, most tissue will be able to be put into culture, however it should be juvenile tissue that will be able to form callus. The most important thing when transferring the tissue into culture is sterilization. All tools and plant parts used should be disinfested and the work area where the transferring is to be done should be sterile. In most professional cases a laminar flow hood is used. The hood takes the air from the room and pushes it through a filter; it then blows the filtered air towards the user to prevent contaminants from outside of the hood from entering. This decreases the likelihood of contaminants in the air polluting the culture. The tissue being used it cut into small pieces and placed on the media. The media contains compounds that are necessary from plant growth such as “mineral nutrients, organic compounds such as sucrose and vitamins, and plant growth regulators” (3). Media can be both liquid (broth) and solid (agar) but both should contain everything the plant needs to grow. The tissue is then incubated to grow and form callus in order to create more tissue. This tissue can be transplanted several times which can leave you with a yield of thousands of plants that came from one tiny section of a leaf.
African Violet Tissue Culture:
In order to supply the demand for African Violets, tissue culture is the most used process to propagate the plant. The media used to grow the tissue in should be prepared ahead of time. The media mix can be bought from multiple companies and they each have their own directions that should be followed to prepare and pour container full of media. One key part of the media is that the pH needs to be adjusted to cater to what the plant you are propagating requires. In this case, the African Violets should have media with a pH of about 5.6-5.8 (3).
· Step 1: Choose plant tissue to propagate. Keep in mind that you should use juvenile tissue. For the sake of sterilization, even though roots can be used, they are much harder to sterilize which leaves more room from contamination.
· Step 2: Wash the tissue in tap water and soak it in a 10% bleach solution for about 10 minutes which should sterilize the tissue (3).
|Laminar Flow Hood|
· Step 3: Once the tissue is disinfested it can be taken to a sterile surface such as a laminar flow hood or a plastic bin that has been sterilized and set on its side in order to prevent contaminants entering from the air. Another method that can be used is to work next to an open flame such as a Bunsen burner so that the flame makes the air rise and keep the contaminants from getting into the media (3).
· Step 4: Wash the bleach solution off of the tissue using sterilized water
· Step 5: Place the tissue on a sterilized surface and using a knife and forceps that have been sterilized, cut the tissue into pieces about 1.5 cm long. Avoid using any tissue that looks white or damaged from the bleach solution (3).
· Step 6: Place the pieces of tissue into the pre-poured containers of media. Space out the pieces so that they are not smothering each other. Use the forceps to gently push the tissue to make sure it comes in contact with the media but not so that it is completely engulfed.
· Step 7: Seal the container tightly making sure nothing can get in and contaminate the media.
|Plant Grown in Tissue Culture at Home|
· Step 8: Place the container in an area such as a growth chamber where it can get approximately 16 hours of light each day and the temperature is around 75 degrees Fahrenheit. The temperature can be colder however the tissue will take longer to grow in colder temperatures (3).
· Step 9: Allow 5-6 weeks for growth to form. When the tissue is big enough pieces can be transplanted into another jar of media which would repeat the process and create more cloned tissue. Or they can be planted into a sterile potting soil. The only issue with taking the tissue out of culture is that it needs time to adjust to the new conditions and therefore should be kept moist and not put under stress from too much light. (3)
Other Methods of Propagation:
African Violets can be propagated in other ways, however they are less efficient and will produce less clones or offspring.
One method of propagation is taking a leaf cutting. This method is simple; you use a sterile knife to cut off one or two leaves from the stock plant. The leaves are then dipped into rooting hormone, planted into moist potting soil and covered with a plastic bag. They should be placed into a well-lit area. If the bag has condensation on it, it can be removed until the plant dries, however the soil needs to be kept wet at all times. In about 3 or 4 weeks the new plants should be rooted and be able to survive without the plastic bag. This method is very successful however growers would need a very large supply of stock plant to be able to propagate as many clones as would be made in tissue culture. (4)
Another method is propagating the plant by seed, however very few cultivars are able to reproduce this way (1).
(1) - "African Violets." African Violets. Auburn University, n.d. Web. 17 Mar. 2013 http://www.ag.auburn.edu/hort/landscape/African_Violets.htm
(2) - "African Violet." Yenra. The Violet Barn, 8 Mar. 2002. Web. 17 Mar. 2013 http://www.yenra.com/african-violet/
(3) - "PLANT MICROPROPAGATION USING AFRICAN VIOLET LEAVES." Plant Micropropagation Using African Violet Leaves. Iowa State University, Sept. 1995. Web. 17 Mar. 2013. <http://www.biotech.iastate.edu/lab_protocols/AV_Micropropagation.html>.
(4) - "How to Propagate an African Violet." Houston Chronicle. Houston Chronicle, 2007. Web. 17 Mar. 2013. <http://www.chron.com/life/gardening/article/How-to-propagate-an-African-violet-1549544.php>.