Propagating an Apple Tree by Grafting

Introduction:

http://en.wikipedia.org/wiki/Apple#Production

            Malus domestica more commonly known as the apple tree is one of the most widely cultivated fruits by tree today. The trees originated from central Asia from their ancestors Malus Sieversii. The apple tree has come a long way through history, from being cultivated all throughout Europe and brought over to North America by colonists. As well as being a prominent figure in mythology; from stories like Johnny Apple seed to Snow White, and even the Bible. Today the genome of the apple tree has been sequence and we are moving toward understanding and controlling its diseases and using for the breeding of new resistant cultivars. (1)

Grafting:

            The technique of grafting has been used for thousands of years, dating back to 2000BC in China (2). Propagation by grafting is the technique where the tissue of one plant is placed on the tissue of a second plant and allowed to grow together creating a chimera. First, a rootstock, or the bottom half of the graft which is a plant that is providing the roots and stability, is chosen for a vigorous root system, drought tolerance, or disease resistance based upon the needs of the propagator (3). Second, a scion, or the top half of the plant that is being grafted onto the root stock, is chosen for desired characteristics such as fruit production, flower production, attracting pollinators, or simple tree growth. The scion and rootstock are then cut in a specific way depending on the plants being used in order to make the most successful graft. The cuts are then matched up so that the vascular cambium, or outer ring of meristematic tissue within the plant that can grow new vascular tissue such as xylem and phloem, are matched up between the two plants (2). This way new vascular tissue that carries nutrients and water throughout the plant can form between the two plant tissues and allow them to survive. After the tissues are matched up the graft union should be wrapped up and kept humid so that the tissues do not lose water while they are healing.  It is important in grafting to make sure that the two plants being grafted are compatible. If they are not compatible, no matter how well the vascular cambium tissue is lined up, the graft will not heal because the rootstock and the scion are too different. Usually two different trees within the same genus would be compatible. The more related the two plants are, the more likely the graft will be compatible (2).

Grafting Apples:

            The most common way of the propagation of apple trees is grafting. In order to graft an apple tree the following steps should be taken:

·         Step 1: Choose the desired scion and rootstock for the apple tree you want to graft. Keep in mind that they both must be compatible in order for the graft to be successful.

·         Step 2: Decide which cut you would like to make in order to graft the stock and scion together. Use a grafting knife and be aware of where your fingers are when making the cut. Some of the more popular cuts are listed below:

o   Splice graft – Slanted cuts are made on each piece of wood, the rootstock and the scion. The cuts are then fitted together on each slant so that vascular cambium is lined up and the graft is wrapped up. (4)

o   Whip and Tongue graft – The same slanted cut is made as if it were a splice graft on each piece. In the middle of the slant, a small straight cut is made into each piece so that when the cuts are put together the notches fit inside each other and increase the likelihood that the vascular cambium will be touching. (4)

Whip and Tongue Graft
http://www.extension.umn.edu/distribution
/horticulture/components/DG0532c.html

o   Cleft graft – The top of the rootstock is cut flat and a cross cut is made to cut the top in half so the wood looks like two half circles. Two slanted cuts are then made on the scion so that the bottom comes to a point at one part but still has a little bit of the wood’s curve at the other end. It will look like a slice of pizza if done right. Up to two scions can be used in this case and they will be placed in-between the diagonal cut on top of the rootstock so that the vascular cambium can match up. (4)

Cleft Graft
http://www.extension.umn.edu/distribution/horticulture/components/DG0532c.html

o   Side graft – A diagonal cut is made into the rootstock along the side of it, but not too close to the roots so that there is enough room for soil. Two cuts are made into the bottom of the scion so that the bottom comes to a straight point. The point on the bottom of the scion is then fitted into the diagonal cut on the rootstock with the vascular cambium lined up. (4)

Side Graft
http://www.extension.umn.edu/distribution/horticulture/components/DG0532c.html

o   Budding – Very similar to grafting except a bud is cut from the scion. A matching cut is made on a bud from the rootstock (there are different ways to make this cut). The scion bud is then fitted into the rootstock and wrapped up. (4)

Budding - How the bud is positioned on the rootstock
http://www.extension.umn.edu/distribution/horticulture/components/DG0532c.html

·         Step 3: A strong tie is used to wrap around where the graft union is and it is then covered with a plastic material in order to keep in the moisture.

·         Step 4: The newly grafted tissue should not be allowed to desiccate and should be kept humid

·         Step 5: You will be able to tell whether or not the graft has taken if growth is seen in the scion. If the scion grows too quickly, it may need to be held up with supports. (3)

Other Propagation Methods:

            Depending upon the commercial use of the apples desired, grafting is the only method of propagation for producing market ready apples (3). Some advantages to grafting are that the material used preserves maturity and takes less time to yield fruit than if grown by seed. Also in certain cases, a plant that would attract pollinators can be grafted onto the same rootstock as the fruit bearing part. Another advantage is that if the cultivar of the scion normally has a weak root system or is not sturdy enough, it can be grafted onto a rootstock that has those characteristics. (3)

The only other way apples are propagated are by seed, however these apples are not what you would normally consider an apple. These apples are usually grown to make hard cider due to the fact that they turn out nothing like the parents that the seed came from. Apples are extreme heterozygotes and when planted from seed they turn out nothing like their parents. (1)

Works Cited:

(1)   - "Apple." Wikipedia. Wikimedia Foundation, 31 Mar. 2013. Web. 31 Mar. 2013. <http://en.wikipedia.org/wiki/Apple>.

(2)   - "Grafting." Wikipedia. Wikimedia Foundation, 31 Mar. 2013. Web. 31 Mar. 2013. <http://en.wikipedia.org/wiki/Grafting#History>.

(3)   - "GRAFTING AND BUDDING FRUIT TREES." Grafting and Budding Fruit Trees. University of Minnesota, 2009. Web. 31 Mar. 2013. <http://www.extension.umn.edu/distribution/horticulture/dg0532.html>.

(4)   - Hartmann, Hudson T., et al. Plant Propagation: Principles and Practices. New Jersey: Prentice Hall, 1997.

Propagating a Honeysuckle by Cutting

Introduction:

Honeysuckle
http://en.wikipedia.org/wiki/Honeysuckle

Lonicera spp. known as honeysuckle is native to the Northern Hemisphere. There are over 180 species and it can be found in both shrub and vine form (1). It can have both decorative fruit and trumpet shaped flowers that can range from white to yellow to red (1). The plant is used mostly for its ability to give cover while also being aesthetically pleasing and very attractive for pollinators. They are also good for erosion prevention on slopes and banks (1). The most widely used way to propagate the plant is through cuttings.

Process:

Taking cuttings from a honey suckle plant is done during late fall or mid-winter. The best cuttings are around 5 inches long of the youngest or most recently growing tissue. If you are taking multiple cuttings, keep the cut ends from drying out by wrapping them in a wet paper towel or placing them in a glass of water. (2)

           

            After the cuttings are taken, place them in pots or containers that allow the media to drain well. A soil-free media should be used. This means it is equally parts perlite, vermiculite, peat moss, and sand. This allows the cuttings to have a bacteria-free environment and prevents disease or contamination from soil. This media also allows for adequate water to be held and available for the cuttings. (3)

            Before placing the cuttings into the media, they need to be prepared. The leaves on the bottom two or three inches should be pinched off because this is the part that is going under the soil and the leaves will only rot and leave an opportunity for the cutting to be exposed to disease. The end being placed in the soil should first be dipped in a rooting hormone. A study done in China on certain species of honeysuckle showed that the most efficient root-promoting hormone treatment was soaking the ends in NAA at 75 µg/ml (4). The optimum time for soaking the cuttings was around 30 to 40 minutes (4).  The cuttings can then be placed into the media so that the hormone treated end is completely immersed in the soil.

            The media should be kept moist. If the cuttings are not being placed in a greenhouse, a greenhouse setting can be mimicked by placing a clear plastic bag or container over the pots to keep a constant temperature or moisture. The temperature should be kept constant around 65 to 75 degrees. Honeysuckle plants usually like to be kept in indirect but bright sunlight and they should be misted frequently to keep a consistent moisture level. Any leaves that die should be removed to prevent the cuttings from getting diseased. (3)

            In about three weeks the roots should start to form and this can be tested by pulling on the cuttings gently. If there is resistance, most likely roots have formed, if not allow it more time under the same conditions.

Other Methods:

This picture shows the method of Layering
http://en.wikipedia.org/wiki/Layering

            Another common method of propagating honeysuckle is layering which involves bending the end of a shoot or vine so that a good portion of it is underground but the top couple inches are above ground. This method usually takes much longer, if done in Spring, the part of the shoot underground may form roots by the end of the season. These are the only two methods of propagation commonly used. Most other methods would be impractical because of the cost or the time it would take compared to taking cuttings. (5)

Sources:

(1)   -"About Honeysuckle." About Honeysuckle. AboutGardenPlants.com, 2004. Web. 17 Feb. 2013.

(2)   - Khan, Tanya. "How to Propagate Honeysuckle From Cuttings." EHow. Demand Media, 12 Apr. 2011. Web. 17 Feb. 2013.

(3)   - Reiley, Melissa. "How to Root Honeysuckle Plants From Cuttings." GardenGuides. Demand Media, 2010. Web. 17 Feb. 2013.

(4)   - Xu HongYan (2004). "Technology for rapid propagation of Japanese honeysuckle [<i>Lonicera japonica</i>].". Xinan nongye daxue xuebao (1000-2642), 26 (2), p. 116.

(5)   - "Honeysuckle Vine Propagation Methods." DIY Home Improvement Information. N.p., 2011. Web. 17 Feb. 2013.

African Violet Tissue Culture Propagation

African Violet Background Information:

African Violet
http://en.wikipedia.org/wiki/Saintpaulia

            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).

Tissue Culture:

General Process:

            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
http://en.wikipedia.org/wiki/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
http://www.hometissueculture.org/

·         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). 

Works Cited:

(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>.