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African Violet Tissue Culture Propagation

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.

Photo Credit: Geiss1136

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

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

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.

Works Cited
Berghage, Robert. Personal Consulting and Lab: “Horticulture 202 Tissue Culture” Paper
Hartmann, Hudson Thomas, and Hudson Thomas Hartmann. Hartmann & Kester’s Plant Propagation: Principles and Practices. Upper Saddle River, NJ: Prentice Hall/Pearson, 2011. Print.
Lineberger, Daniel R., and Mark Druckenbrod. “African Violet Chimeras.” African Violet Chimeras. N.p., n.d. Web. 21 Mar. 2014.
“Saintpaulia.” Wikipedia. Wikimedia Foundation, 21 Mar. 2014. Web. 21 Mar. 2014.

Lilac Propagation

The common lilac (Syringa vulgaris) is a deciduous shrub in the olive family, Oleaceae. Native to the Balkan Peninsula, these plants were first introduced to Europe at the end of the sixteenth century. From there, they were introduced to the American colonies in the eighteenth century. Lilacs are commercially popular as an ornamental plant today because of their bright, sweet-smelling flowers. Lilacs have over one hundred different varieties, making it a very diverse plant loved by many.

When working with plants and cuttings, sanitation is vital. Before you begin, make sure all of the equipment and materials that will be used are sanitized. Even though the common lilac is a softwood, it is a hard to root species. With this information given, the primary method of propagation will be stem cuttings. Because lilacs are softwood species, they can lose water rapidly, so desiccation control is needed.

Propagation Process

  • Stock Plant Selection – Start by selecting a healthy stock plant. A healthy stock plant should have luscious, bright leaves. Examine the plant to make sure it is free of disease and insects. If any sign of disease or insect infestation is spotted, do not use the plant. You should select a branch with moderate thickness. Lilacs are hard-to-root species so a branch that is too thick or thin will not propagate. Because lilacs are softwood, cuttings should be selected immediately after the plant begins to resume growth in the spring or early summer.

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    Common Lilac, Getty Images

  • Cutting Selection – Select approximately three or four stem cuttings from the stock plant to ensure a better survival rate. The cuttings should be between three to five inches in length and contain two to three nodes. While making the cutting, use a sharp pruner or scissors to make a clean cut. Dull blades can damage the proximal end of the cutting.  Make sure your cutting is not too old or too young. To make sure that you have a suitable cutting, select a branch and attempt to break it. If it snaps easily, the branch is of suitable age. If the cutting bends and doesn’t break, the cutting is too young. If the cutting does not bend or break at all, it is too old. Desiccation control is crucial for propagating all softwood cuttings, so it is best to plant them in the media as soon as possible.
  • Rooting hormones – Once you have a cutting, dip the proximal end into water. After water, use auxin, a rooting hormone. IBA is a common type of auxin and will help to establish and promote root growth. Lilacs are softwood cuttings, so to produce desirable results, use 500-1250 ppm. There are many brands of powder, but as long as they have some type of auxin they should suffice. Tap off any excess powder from the cutting before inserting it into the media.
  • Media – Desiccation control is vital when working with softwood cuttings. To ensure drying out won’t happen, use a media that has an excellent water holding capacity. Sand is the primary soil usually used in propagation of lilacs but you could also use peat, vermiculite, perlite, or even a mixture of all four. Fill the pot with the media and wet it down. Use a pot that has holes in the bottom. When water starts to drip through the holes, the soil is moist enough. Use your finger to make a hole in the center of the soil and put your cutting in the hole. Make sure the rooting powder does not come off when you plant it. Water the cutting instantly after it has been planted in the media. This will help to firm the soil around your cutting. Under these conditions, the cutting should root in three to six weeks, but it could take as long as eight.
  • Care – The most important part of caring for a cutting is desiccation control. Desiccation can be controlled using a mist system and keep the plant at a cool temperature. Keep the soil moist at all times. If the soil dries out, the cutting will not form new roots. Using a mist or fog system will ensure that the cutting will be watered regularly. If you do not have access to a mist system, a daily, gentle watering will be adequate. Be sure that your soil is only moist, not completely saturated. Overwatering of the cuttings promotes fugal disease, such as root rot, ceasing root growth. A well ventilated soil and pot will prevent this from happening. Temperature during rooting should be between 23-27oC at the base of the plant. If your plant is in a mist system, the air temperature can get up to 30-32oC, as long as there is adequate lighting. Be sure to remove flowering buds from the cutting as majority of the nutrients are taken away from the roots and given to the flowers.
  •  Bottom heat – Bottom heat can help to induce root growth. Optimum soil temperature for rooting softwood cuttings is between 21-24oC. Commercially, bottom heat can be done in two common ways: with forced air furnaces or a hot water system. If you are not propagating your plant in a greenhouse you can use heating cables or heating mats as an alternative source for bottom heating. On days when the air temperature is warmer than recommended, lower the temperature of the bottom heat. The combination of high air temperature plus bottom heat will cause the soil to dry out rapidly. If you are using bottom heat, pay extra attention to the moisture content to ensure that the plant won’t desiccate.

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    Common lilac, Syringa vulgaris. Photo by Georges Jansoone, from the Wikimedia Commons

  • Transplanting – Starting checking the plants within the 3-6 week rooting period to observe the establishment of the roots. Once substantial rooting has been made, you may place the plant in a desirable location. It is crucial to prevent transplant shock. Prevent this by slowly reducing the amount of water the plant is getting, by changing intervals and times of the mist system, or manually do not water as frequently. As you reduce water intake of the plant, you will want to simultaneously reduce the air and basal temperatures until they mimic the environment that the plant is going to be placed in. Once transplanted, allow two or more years for the lilac to bloom.

Other propagation techniques:

There are other less popular propagation techniques that can be used on lilacs. Other methods of propagation include propagation by seeds, grafting, air layering, and tissue culture.

  • Seeds – time consuming (3-4 years to blossom, 40-60 days of stratification)
  • Grafting – difficult for an amateur due to all of the elaborate steps and time consuming
  • Air layering – simple and easy. Start by wounding the stem of the lilac plant. Put a rooting hormone in the wound. Then cover the wound and replant it.
  • Tissue culture – very difficult to keep free of bacterial and fungi. Need a completely sterile environment.

Conclusion

This lilacs bright, vibrant colors make it a beautiful ornamental tree that is loved my plant enthusiasts everywhere. This plant is relatively easy to propagate using stem cuttings. The most important thing to remember is to prevent desiccation. Do not leave the cutting out of the ground for longer than needed and keep the soil constantly moist. If you follow these steps, you should be able to successfully propagate this lively ornamental shrub.

 

Works Cited

Bruins, Elizabeth. “Propagation of French Hybrid Lilac.” N.p., n.d. Web. 22 Feb. 2014.
Downey, Lillian. “How to Root Lilac Cuttings.” Home Guides. Demand Media, n.d. Web. 22 Feb. 2014.
Hartmann, Hudson Thomas. Hartmann & Kester’s Plant Propagation: Principles and Practices. Upper Saddle River, NJ: Prentice Hall/Pearson, 2011. Print.
Richards, Julie. “How to Use Bottom Heat to Propagate Your Cuttings.” Home Guides. Demand Media, n.d. Web. 22 Feb. 2014.
“Syringa Vulgaris.” Wikipedia. Wikimedia Foundation, n.d. Web. 22 Feb. 2014.