Plants, in nature, are extremely delicate organisms. In their environment, plants are exposed to many hazardous elements that may prohibit their growth or inhibit their reproduction. Because of the fact that seedlings are not assured to root and flourish, nurseries have developed a simple yet highly effective method of plant reproduction called "Cutting" that greatly increases product yield. Extremely resourceful, this process enables mass production derived from a single source plant. An inexpensive procedure, costing virtually nothing, cutting is able to produce many offspring from excess branches that would most likely be pruned for aesthetics. This experiment will span a four-week time period and will help determine in which growing media-sphagnum peat, sand, vermiculite, potting soil-cuttings root the best in.
There are many methods of cutting that nurseries use to propagate plants. These methods vary the location of the cut on the stem and the shape of the cut. Some examples include tip, medial, cane, single eye, double eye, heel, and leaf cutting. There are numerous types of plants that can be propagated using cutting but for this experiment the lilac plant will be used along with the tip cutting method. The reason plants can take root from cuttings is that each cell in the plant has all the genetic information necessary to produce a complete plant. When a cutting is taken the connection between the stem and the root is removed. The changes in growth patterns are regulated by plant hormones produced in the leaves, stems and roots of the plant. Once a cutting is taken, the plant hormones no longer travel back and forth between the roots and the stem. The change signals the plant to first heal the wound, and then replace the missing roots.
· Lilac Plant
· Sharp cutting utensil
· Pete moss*
· Potting soil*
· Clay/earth *
· 4 one-gallon plant growing containers
· Rooting hormone
· Dixie Cups
The first step is to fill each of the 4 one-gallon containers with the four growing media (sphagnum peat, sand, vermiculite, potting soil). Next, locate 40 young branches of approximately the same size in diameter and remove them from the plant using your sharp cutting utensil. Remove all of the flowers and flower buds from the cuttings, this is done so that the cuttings can conserve energy. Using the ruler, measure each branch's length and record the measurement on the data sheet. Locate a node on each of the branches, and proceed to cut a 45-degree angle approximately one-eighth of an inch below the bud using your sharp cutting utensil. Dip each severed end in the rooting hormone and then moisten with water. Applying rooting hormone speeds up the rooting process by reducing the time that the cuttings need to generate the hormonal changes the plant needs to change its growth patterns. Place ten cuttings in each of the four filled containers, three inches away from each other and two inches into the media. Every other day water each cutting, using ¼ of a Dixie cup full of water, being sure not to flood the media.
After the cuttings are planted measure each once a week and note how much it has grown. Compare it to its original height and determine the percent it has grown-record data. At the end of the four-week time period, up root each specimen and determine the number of successfully rooted plants in the four different media. Then using a simple equation, which is the original height divided by the height at the end of the week to determine the percentage of success in each media.
After five weeks of thoroughly watering our specimens every other day as scheduled, we were frustrated and disappointed to find that no signs of propagation took place. With a deficiency of results we turned to further research to investigate possible reasons for our lack of success. According to Ray R. Rothenberger of the Department of Horticulture of the University of Missouri-Columbia, "tip cuttings may be subject to rot during rooting," therefore avoiding excessive moisture while maintaining proper humidity levels is key to producing the best results. It is quite possible that we over-watered our studies. Because the cuttings were isolated individually in rather small growing containers, it is likely that the drainage of excess water from around cutting was prohibited.
Contamination may be another possible reason we received flawed results. At the start of our lab, we failed to realize how essential sterilization is to success. We washed our equipment thoroughly with water, however, upon further research, the Department of Horticulture suggests that sterilization should be accomplished use extreme temperatures such as an oven set to 150-200 degrees Fahrenheit. Pots and tools should be rinsed thoroughly with alcohol and a disinfectant such as a household cleaner.
It is possible that the plants endured a state of shock as we took them from a cool, dry, outdoor, September environment and situated them in a warm, humid greenhouse. A horticulturist from a nursery in Oxford informed us that a plant must first recover from a drastic change in environmental conditions before rooting may begin.
Softwoods, by nature, absorb nutrients with greater ease than hardwoods. This enables them to root in less time than the hardwood samples used in our experiment. For optimum results we should have used softwood, due to the fact that softwoods cuttings are best taken during the months of June, July, August, and September (according to horticulturists James T. Midcap, Gary L. Wade, and Melvin Garber).
Last, but certainly not least, human error could have been a primary factor in our lab. "CAUTION: Remove leaves only from the lower half of the cuttings. The loss of too many leaves results in an inferior cutting!" reads a statement from the University of Georgia's Cooperative Extension Service. Misunderstanding some advice, we remove every leaf from our cuttings with the intention of limiting wasted nutrients and energy. What we failed to realize is that the hormone that triggers rooting is contained within chlorophyll. By removing the leaves, we removed the essential hormone for the rooting process, not to mention that leaves provide necessary energy, through photosynthesis, for a healthy plant to survive.
In conclusion, the numerous amounts of precautions we could have taken in order to produce results include: improper watering of plants, unsanitary equipment, subtle temperature changes that may have caused shock, and finally human error such as the removal of leaves from our specimens. These problems could have been prevented had we not rushed into the futile grafting project. Had we not wasted time on the prior project, we would have had the necessary time to better research and perform the required precautions. This would have helped us produce the roots we had anticipated.
Analyzing the data to try to determine the meaning behind the results such as why a certain medium might work better than a different medium. Also answer the question, what is the best growing medium out of those tried? In a future experiment you could use different plants and see if the results hold true for them.
Home Propagation of House Plants -- Ray R. Rothenberger
Department of Horticulture, University of Missouri-Columbia
Agricultural publication G06560 -- Reviewed October 1, 1993
Introduction to Plant Propagation:
Propagation from cuttings:
Propagating Shrubs from Cuttings -- James T. Midcap, Gary L. Wade and
Melvin Garber, Extension Horticulturists
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