Attack of the Killer Cabbage Clones
AbstractDo you like to watch outdated science fiction and cheesy horror movies? Many fictional tales of cloned organisms have been created based upon the scientific method for cloning animals or plants. In the real world, the cloning of plants is a common method used in modern farming. How do you clone a plant? In this science project you will get to find out by making your own cabbage clones!
ObjectiveInvestigate which part of a cabbage is best to use for making a cabbage clone.
Plants, like animals, have a way to reproduce and make new baby plants. Unlike most animals, plants commonly use two different ways to make new plants. A plant will use one way or the other, depending on what the environment around them is like at the time. These two different types of reproduction are called sexual reproduction and asexual reproduction.
Many plants we are familiar with, such as flowering plants, undergo sexual reproduction by making seeds. Each seed contains the embryo, or baby plant, that will grow into an adult plant under the right conditions. Sexual reproduction requires both male (boy) and female (girl) parts of a plant, which mix together to form the embryo. Because the embryo is a mix of both parents it is not identical to either instead it is its own unique combination. Because it is unique it increases the total amount of variation in the population. In this way, sexually reproduced plants are diverse.
Asexual reproduction in plants is when new plants are made without male and female parts mixing together, and it can be done without making seeds. Asexual reproduction only requires one parent. The new baby plant is a clone (copy) of the parent plant, meaning it is identical and has the same same DNA as the parent plant. Because of this, asexually reproduced plants are usually not as diverse as sexually reproduced ones.
Even though asexual reproduction produces plants with very low diversity it has many useful applications. Cloning plants is very common in agriculture because a plant can often be made relatively quickly this way. It also allows a farmer to grow more reliable produce. If you have a delicious sweet tomato you do not want to risk adding diversity that may make the the tomato sour. Instead you want to keep exactly the same delicious sweetness. Using asexual reproduction, a farmer can essentially grow the exact same plant from one year to the next year.
In this plant biology science project, you will investigate which part of a cabbage is best to use for making a cabbage clone through asexual reproduction. You will remove the leaves from a cabbage and then cut its stem into three parts: top, middle, and bottom. The bottom will be closest to where the roots were, while the top will be closest to where the leaves were. Will all parts re-grow into a cabbage, or will some parts not work and die? Will some parts turn into clones much better than others? To help you form your hypothesis, here is a hint: Plants have a type of tissue called the meristem and this is where plants can grow from. Meristem tissue is usually at the tips of a plant's roots and the tip of the stem, where new stems, leaves, and buds grow from. How do you think this will affect which part of the cabbage best turns into a clone?
Terms and Concepts
- Sexual reproduction
- Asexual reproduction
- How is asexual reproduction different from sexual reproduction?
- Which part(s) of the cabbage stem do you think will work best for making a clone?
- How does plant cloning benefit modern agriculture?
BibliographyVisit the website of "The Great Plant Escape" to help Detective Le Plant solve 6 cases, learn about plants, use the glossary to learn new terms and see pictures of plant parts:
- Stack, G., et. al. (n.d.). The Great Plant Escape. University of Illinois Extension. Retrieved March 1, 2013.
Visit these webpages to learn more about plant reproduction:
- Biology2Kids.com. (n.d.). Plant Reproduction - They'll Make More. Retrieved February 28, 2013.
- Encyclopedia Britannica, Inc. (2011). Plant Reproduction: Asexual Reproduction. Retrieved February 28, 2013.
For more advanced information about plant meristems, visit this webpage:
- Kids.Net.Au. (n.d.). Meristem. Retrieved February 28, 2013.
This project idea was inspired by the following resource:
- Bochinski, Julianne. 2004. The Complete Handbook of Science Fair Projects. Hoboken, NJ: John Wiley & Sons. pp 68-69.
Materials and Equipment
- Fresh heads of cabbage (3). We recommend using Napa cabbages, which are longer than the more common round cabbage, because Napa cabbages are less dense, easier to pick apart, and have longer stems. They are available at most grocery stores.
- Cutting board
- Optional: Piece of paper and pen or pencil
- Paper towels (9)
- Small sealable plastic bags, such as 6.5 x 5.9 inch "sandwich" bags (9)
- Optional: Scissors
- Optional: Camera
- Permanent marker
- Cookie sheet or large tray
- Adult helper
- Lab notebook
- Remove the leaves from one of your three cabbages.
- Beginning with the outer leaves, pull all of the leaves of the cabbage off of the stem. Do not worry if you do not get the entire leaf removed, as it is better to leave some of the leaf attached than to risk damage to the stem.
- When you are completely done removing the leaves, your stem may look similar to the ones in Figure 1. Since you do not need the leaves for this project, when you are done removing them, you might like to use the leaves to make a yummy cabbage soup or coleslaw!
Figure 1. When you are done removing the leaves from your cabbage, the stem may look similar to these ones.
- Repeat step 1 with your other two cabbages.
- Place one of the stems on a cutting board and, with an adult's help, use a knife to carefully slice the stem cross-wise into three pieces, as shown in Figure 2. Try to make each piece about the same width.
- Make sure to keep track of whether each piece is the bottom, middle, or top piece. You can do this by setting them on a piece of paper and labeling the paper near them or observing how they are different.
Figure 2. Cut each cabbage stem into a bottom, middle, and top piece, as shown here (using a single cabbage stem). Make each piece about the same width.
- Repeat step 3 with the other two cabbage stems.
- Keep track of which stem the pieces came from and whether each piece is a bottom, middle, or top piece.
- Prepare sealable plastic bags to clone your cabbage pieces in.
- Fold a paper towel in half and then fold it in half again, as shown in Figure 3.
Figure 3. Fold a paper towel in half twice, as shown here with the dotted lines.
- Slip the folded paper towel into a sealable plastic bag so that the last fold you made is at the bottom of the bag.
- If the folded paper towel is too long to fit in the bag, have an adult help you use scissors to trim the paper towel so that it just barely fits.
- Fold a paper towel in half and then fold it in half again, as shown in Figure 3.
- Add water to the bag so that the paper towel is damp, but do not add so much water that it is dripping wet. Pour out any extra water. It will probably take about 2 Tablespoons (tbsp.) of water total.
- Repeat step 5 eight more times so that you have a total of 9 bags prepared.
- Assign a number to each stem (from 1 to 3).
- If you have a camera, take a picture of each stem piece.
- Include a label in each picture, such as "Stem 1, bottom piece" written on a piece of paper next to the stem piece, so that later you know what the picture is of.
- If you do not have a camera, try to make drawings of the stem pieces in your lab notebook. Label each drawing and use colored pencils, pens, or crayons to color it.
- In your lab notebook, create a data table like Table 1.
- You will be recording your observations in a data table like this one each day.
|Stem||Stem Piece||What color is it overall?||Are there green leaves?||Are there small, green spots?||Are there brown, slimy spots?||How does it smell?||Does it look like it is becoming a clone?|
- Examine each stem piece and record your observations in the data table in your lab notebook, answering each question for each piece.
- After making your observations, put one stem piece into each bag you prepared. Use the permanent marker to label each bag with the stem number (1 to 3) and piece (top, middle, or bottom).
- Put each piece in the middle of the folded layers of the paper towel. There should be two layers of paper towel above the piece and two layers below it.
- Blow a tiny bit of air into each bag before sealing it. Your breath has carbon dioxide (CO2) in it, which helps plants grow.
- Place all nine sealed bags on a cookie sheet or tray.
- Place the tray near a window and leave it at room temperature. If the bags are properly sealed, you should not need to add water. You may notice that water begins to condense and form droplets inside the bags, which is normal.
- The next day, open the bags one at a time to look at the cabbage stem pieces.
- Repeat steps 8-14. Make a new data table, similar to Table 1, to record your results in for this day. Make sure to label this data table Day 2.
- Do the stem pieces seem to have changed? Do some look like they are becoming clones? How can you tell?
- Repeat step 15 six more times so that you have been making daily observations for one week after you started the experiment.
- Do not forget to make a new data table, similar to Table 1, to record your results in for each day. Make sure to put the day (e.g., Day 3) on the top of the data table.
- If you want, you can repeat step 15 additional times to see how the stem pieces continue to change over time. Do any clones continue to grow?
- Check out the Variations in the Make It Your Own tab for tips on continuing to grow your clones.
- Analyze your results.
- How did the stem pieces change over time? Did some turn into clones? Did some seem to become smelly and rot?
- Did some types of pieces (top, middle, or bottom) become better clones than others? How can you tell? Did some types of pieces make the worst clones?
- If some pieces became better clones than other pieces, why do you think this is? Hint: Re-read the Introduction in the Background tab and think about what the meristem tissue does and where it is located on the plant.
Ask an Expert
- You can try to continue growing the clones you started in this science project. To do this, after the stem pieces have been growing in the paper towels for around 10 to 12 days, remove them from the bags. If the pieces are rotting anywhere (in other words, there are brown, smelly, slimy parts on the stems), have an adult help you carefully cut off the rotting parts and discard them. Put potting soil in a plastic container or a pot and add water to make it very damp. Put each stem piece on the damp potting soil. Watch the pieces each day to see how they change. Do the leaves grow? Do they sprout roots? Do they turn into plants like the original cabbage you used, or are they different somehow? You will need to keep the soil moist for the pieces to grow so you may need to water them every 3 to 5 days or so.
- You can clone other crops as well. Do the clones come from the same part of the plant? Do other crops need different conditions to be cloned? Are some crops cloned much more easily than others? Try using parts of the celery stem, tubers of potatoes, slices of carrot, lettuce stems, separated garlic cloves, etc. You may want to have an adult help you do some additional background research to get ideas of how to try cloning these different crops.
- Cloning is important for agriculture because it increases the speed of crop production and the yield of crops. How much faster is cloning a vegetable than growing it from seed? Try an experiment comparing the time it takes to produce a mature lettuce or cabbage by cloning and by growing from seed. How much faster is it? What is the yield from each method?
- Do clones develop better when grown on some materials compared to others? In this science project, you tried growing clones on damp paper towels, but how well would other materials work? Use the type of pieces that turned into the best clones from this science project (top, middle, or bottom pieces) and repeat this science project by trying to clone these types of pieces on other materials, such as soil, manure, wood mulch, shredded paper, dead leaves (which tend to be acidic), grass clippings (which are rich in nitrogen), fertilizer pellets (also rich in nitrogen), or rotting fruit or vegetables (release ethylene gas). Which material leads to the best cabbage clones? Which material is the worst to use?
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