African violets (Saintpaulia) are a genus that consist of 6-20 herbaceous flowering plants. Today, these plants are primarily cultivated as common indoor house plants, but they also have cultural association to mothers. Because of this association, African Violets have been traditional presents to give to Mothers; specifically for Mother’s day. African Violets also are accompany with Easter and Valentine’s Day. As its common name suggests, the African violet is native to Africa; it can be found native in the countries of Tanzania and Kenya. Despite the common name, African violet, it is not actually a true violet, but instead has a superficial resemblance to them. Unfortunately, several species of African violets are endangered or threatened due to their native land being cleared for agricultural use. The following webpage will give step by step directions for using tissue culture to propagate African violets.

African Violet Photo Credit: Geiss1136

Materials:

• African Violet (Saintpaulia) plant
• Media in petri dishes
• Disinfectants, soapy water, Clorox for sterilization
• A scalpel, tweezers, and tool rack
• Bacticinerator for sterilization of tools

Steps in Tissue Culture Propagation:

All plants share four common stages in micropropagation that will need to be followed:

Stage 1: Select an explant and place it into a sterilized culture in an in-vitro environment that promotes stable shoot growth

Stage 2: Maintain a stable culture while increasing shoots

Stage 3: Produce roots on the microshoots

Stage 4: Harden off the microcuttings so they can survive and thrive outside of the tissue culture

African Violet Photo Credit: SeriouslyFlowers.com

Media

Preparing the correct media is essential to culture success. Media provides the plant tissue with the nutrients that it needs. The recommended media for African Violets is Murashige and Skoog (MS) basal medium that contains supplemented vitamins. The supplemented vitamins make the process much simpler for the grower, reducing the chance of error. Add 30g/1 of sucrose along with 170 mg/1 of monosodium phosphate to give the tissue an adequate amount of carbohydrates. Next you can add plant hormones Auxin and Cytokinin. Add these hormones in the forms of 0.1 mg/1 of Naphthalene acetic acid (NAA) and 0.01mg/1 of Benzyladenine respectively. The desired pH for the culture will be 5.7. Add either HCL or NaOH in order to raise or lower the pH respectively. Then use 2g/L of phytagel to solidify your medium. Once all of your ingredients have been added, autoclave the medium for 15 minutes.

Explant Selection

Once your media is prepared, you may select your explant. The explant is simply the part of the plant that is taken from the stock plant which is going to be propagated. Be sure to select a stock plant that is healthy, has good aesthetics, and is free of diseases. If there is any health problems at all with the stock plant, it will not propagate. Select a leaf and petiole from the stock plant and cut it with a scalpel or scissors; this will be your explant. An explant of 3-5cm will suffice. Wash the explant in soapy water for about 30 seconds. Shake off the excess soap and water, then submerge into a solution of 10% Clorox for 15 minutes to disinfect the plant tissue. Be cautious of this timing. If the explant is in the Clorox solution for more than 15 minutes, it will die. If the explant is not in the solution for the full 15 minutes, there is a risk of contamination.

Laminar Flow Hood

Once the explant has been sterilized, move to the laminar flow hood. The laminar flow hood constantly circulates air to reduce the amount of airborne pathogens. Be sure to wash your hands and clean your work area with a disinfectant before starting. While working in the flow hood, work towards the front of it; this is where most of the air circulation occurs. Though it will feel uncomfortable, sit up straight and do not look over your work. This will help to prevent bacteria from being transported from you into your culture. Now you may start working with the explant.

Cutting the Explant and Transporting into Media

Remove the explant from the Clorox solution and thoroughly rinse it off with sterile water. Then place the explant in a sterile petri dish that you are going to be working in. Before any tools touch the plant, sterilize them using the Bacti-Cinerator. Begin by removing any damaged parts of the plant that won’t be suitable for propagation. Cut the leaf blade and petiole into sections of approximately 1cm. Distribute the explant pieces evenly throughout the petri dish of medium. Lay some pieces of the leaf upright and others upside down. Just like the leaf, you can lay some parts of the petiole onto the media vertical and others horizontal. Press the explant onto the media, but do not fully submerge it in the gel, as this will kill it. As stated before, it is crucial that you do not lean over your plate as you are transferring the media. Once all of the explant is transferred into the media, seal the petri dish with parafilm wrap and put it in an incubator.

Incubation

Once your petri dish is sealed, place it in an incubator. Watch out for any bacteria that will appear in the form of fuzz or slime. Bacteria will easily be noticed within one week. If you find any amount of bacteria growing in the petri dish, it is no longer suitable for propagation and should be discarded. The plant material should respond to the culture media within 4-6 weeks of incubation. Within that 4-6 weeks, the plant material should produce shoots or roots.

Post Incubation

The small plantlets that should appear within the 4-6 week period can be taken out of the tissue culture and transplanted into a small foil container that contains Reddi Earth soilless media to begin root establishment. Keep the plant in a greenhouse mist system for

Shoots that will grow from tissue culture. Photo Credit: Daniel Lineberger

another 3-5 weeks and the plants should be well rooted. From this point, transplant the plantlet into a plastic pot that contains Metromix 350 soilless media. Keep the plant in the greenhouse, but make sure there is approximately 70% shade on it. Once the plant has shoots and established roots, they can be transplanted into potting soil.

Conclusion

The African lilac has been a common household plant with its luscious purples flowers, and will remain popular in the years to come. Even though tissue culture is no easy task, practice, along with trial and error will give anyone the skills needed to propagate this plant.