We used two class periods to finish a movie called The Island. This movie reveals both scientific and ethical questions about cloning human beings. To me, cloning human beings is a messy business, and it is an unspoken rule among the scientists that no one is allowed to clone humans. Since cloning human beings is forbidden; yet, cloning does have some benefits. Then how about cloning plants? My friend Alvin proposed this idea, which inspired me. He stated as following:If we can "clone" animals and humans, then we can also clone plants, right? Then, If we can clone plants, can this be utilized by farmers and produce growers to save money?
For this particular question, we assumed that plant cloning is easier than animal/human cloning. Also, plant cloning would not involve too many ethical questions. Following is some research on plant cloning.
I. Methods of cloning plants:
1. Ground Layering – burying the branch:
Plants that have branches near the ground can be buried in the middle with the tip sticking up. This will provide nutrition from the main plant while the rooting takes hold. This works well for vines such as grapes and muscadines. There really isn’t much to learn. Bury the middle section in healthy soil and let it take hold. It’s a common practice to steak the plant up and wound the area that needs rooting. Breaking the bark can spur root growth, but unlike cuttings, the clone will be fed by the main plant during the cloning process. Applying a rooting hormone is also recommended and will improve success.
2. Air Layering:
This type of cloning takes a little more skill, but works well with hard to clone species. Air layering is to peel back the top layer of a branch and wrap the branch with a small bag of grow medium. To air layer, take a sterilized knife, cut away a 1-2 inch section of the bark below a node. Be careful not to cut too deeply. The xylem carries nutrition to the branch. If it is cut, the branch will die. To air layer, follow these steps.
1. Sanitize all tools that will be contacting the exposed bark.
2. Find a branch that has at least two nodes and is 1/8th inch or bigger. Smaller than 1/8 probably will not hold the weight of the branch and bag.
3. Cut away a section of the outer layer of the bark / skin of the branch. Cut deep enough to remove the bark, but not deep enough to sever the xylem.
4. Place a plastic bag / sleeve over the branch. Secure the area below the cut with tape around the bag. Make it snug, but don’t strangle the branch.
5. Apply rooting gel or powder to the cut away area.
6. Pack a grow medium around the cut away area. Perlite, unfertilized peat moss, sphagnum moss, and orchid moss are great options. Moisten the grow medium, but don’t saturate. It should feel like a damp sponge.
7. Tape the bag closed in the area above the cut. The bag should be secure, but not tight.
8. With a pin, poke holes in the bag to allow air flow.
9. Every few days, add a few drops of water to keep the medium moist.
It should take 2 to 3 weeks. When roots are clearly visible, cut the branch and carefully remove the bag. Transplant into quality soil and establish indoors. Once the plant is thriving, it can be transplanted outside.
Another option for air layering is to cut a diagonal incision halfway through the branch. Place a toothpick in the cut to keep it from closing up and grafting back in. The rest of the steps are the same as above.
Clonex s a great rooting gel that I use and highly recommend.
3. Cloning Cuttings.
This is my favorite style of propagating, and it will work with most plants. In fact, if you buy plants from a local garden center, most likely they weren’t grown from seeds; they were cloned. Take a look at this photo:
Take a close look at the root area. This came from a garden center and it is clearly a cloned tomato. Notice that the roots are coming out of a cutting. So when you buy well established plants, they are usually cuttings that have been rooted.
Cloning is an efficient way to get a jump start on your plants. And the quality of the plant is great because it is coming from a healthy mother plant. This can be especially helpful for hybrids that can’t be propagated by seed. Some hybrids are patented, so just be aware of this fact when you are considering cloning an exclusive hybrid.
Some growers have cloned more than 20 generations on their tomatoes.
To clone cuttings, pick a healthy branch that has no flowering taking place. Tomatoes are more forgiving than other plants, but flowering can be a disaster for cloning for most other plants. Plants produce completely different hormones when going through the flowering stage. Unlike many other plants, tomatoes grow while blooming, so they can still clone, but it’s more effective to go with non-flowering stalks if you can catch them before they put out buds.
When a flowering plant is cut, the plant has to stop producing fruit and flower hormones, and it attempts to switch over to growth and rooting. A cutting has limited resources, so it rarely survives the transition from flowering to rooting. For this reason, try to pick a branch that doesn’t have flowers and doesn’t have flower buds. If your tomato cutting has small flower buds, pinch them off. You don’t want flowers to develop until the plant is ready to produce.
A good place to take a tomato cutting is where a sucker is growing in the crotch area of two branches. See the photo below:
The sucker grows out and will become a new branch with flowers and tomatoes. While it’s young, a sucker is a great cutting to take for cloning.
When cloning, follow these steps:
1. Sanitize a cutting instrument – knife or scissors.
2. Cut at a 45 degree angle. The angle provides more surface for roots to emerge. Don’t let the cut surface dry out. It’s good to drop the cuttings into a cup of water until you can plant them.
3. If you are growing hydroponically, prepare a grow medium such as rock wool or perlite. Soak the medium in a rooting solution. Clonex is a great option. If you are growing in soil, soak Jiffy plugs or apply rooting solution to soil. You can also buy rooting soil that has nutrients especially for cuttings.
4. Dip the cut in either a rooting gel or a rooting powder. Place the cuttings into your soil or grow medium.
5. Keep the medium moist by watering daily. I like to use a mist sprayer to keep the plants moist and watered. Use plain water.
6. If possible, place your cuttings into a seeding dome. This will keep moisture in. After four days, I like to remove the dome. Some plants can become susceptible to fungus if they stay in heavy humidity.
Tomatoes are more forgiving, and people have had success by just poking them into the garden soil. However, your success rate and overall plant health will be better by using rooting solution and dipping the cuttings in rooting gel or powder. Other types of plants are less forgiving and need more care.
These two products work great together. Dip the cutting tip into the Clonex rooting gel, and soak the grow medium or soil plug into a Clonex diluted solution. 1-2 teaspoons per quart is all you need. Jiffy plugs soaked in a rooting solution works very well for tomatoes. If soaked in a Clonex solution and dipped in gel, the roots will fill the plug in less than a week. When rooting for soil growth, I use Jiffy plugs and Clonex. When prepping for a hydroponic system, I use Clonex and plug the stem into rock wool.
II. Pros of cloning plants
There are numerous advantages of plant cloning like;
- It helps in producing individuals of same species faster and in desired quantities.
- It is like a quick and relatively speedy method to fulfill requirements of large quantities of a single species plant.
- Since all cloned plants will grow in fixed time, it is easier to predict the time between planting and harvesting. In an agricultural economy, this can be a great boost to crop cultivation and earning for farmers.
- Plants with better resilience toward pesticides and chemical fertilizers can be produced by cloning.
- It is a cheaper option than conventional methods of growing plants. You just have to cut a twig, stem and plant it using some methods of cloning.
- By growing a single plant with excellent nutritional benefits, one can clone it to get similar plants with same benefits. This can help to solve issues of poor vegetable and fruit quality.
- Since yields can be faster through plant cloning, issues of food problems can be resolved by producing large quantities of crops.
III. Cons of cloning plants
Disadvantages of plant cloning have become a topic of concern for environmentalists and botany scholars who are concerned with several features of plant being destroyed due to cloning. Here are some demerits of cloning a plant.
- Genetic diversity is adversely affected due to cloning. Same species, with same sets of features may be produced in great quantities, but there is a lack of genetic variety in cloned plants. In nature, this doesn't happen. Every individual plant, irrespective of being of the same species, has its own tolerance towards diseases and environmental changes. In cloned plants, this is a major drawback. Cloned plants cannot withstand changing environmental factors and if a disease strikes even a single cloned plant, it can wipe out the entire crop.
- Since cloned plants are identical in looks, it can be disadvantage to use them for decorative purposes. Home gardening and landscaping can eventually turn out to be monotonous.
- Natural evolution of plants, if hindered can lead to imbalance in natural way of vegetation and growth of crops.
- There remains a question mark on the future of plant cloning. It is unpredictable and still lots of research is required to understand the issue of genetic variation.
- If plant cloning is done on an extensive scale, there is a possibility of food becoming more commercialized. While numerous third world countries can be helped for food shortages, it can't be denied that those in power will not lose the opportunity to commercialize plant cloning for gaining more control of food reserves.
- Problems of deforestation that is believed to be solved by plant cloning, again carries the threat of triggering poor bio diversity. We know that forests are one of the exemplary examples of rich bio diversity. If same species are planted, richness of diversity is bound to decrease.
* Sources gained from Buzzle:
http://www.buzzle.com/articles/disadvantages-of-plant-cloning.html
