Vegetative propagation is the process of multiplication in which a portion of fragment of the plant body functions as propagates and develops into a new individual. Some plants are able to multiply by vegetative techniques which involve the production of new plants without the act of fertilization or sexual union.
This type of propagation works only in plants. In physical amplification, parts of old plants such as stem, root and leaf are used to grow a new plants. When plants present in the inactive condition in the old plants are given favorable conditions such as moisture and heat, they begin to grow in the form of new plants and begin to develop.
Vegetative propagation is probably something very peculiar to the plants. The very same feature is also exploited for the commercial value and by avid gardeners who know the plants well. You do not always need seeds to grow plants. New plants can grow from the older plants, through the method of vegetative propagation such as grafting, layering and budding. It is a form of asexual reproduction which is seen in plants. Here only a single plant is involved and the offspring that arises is identical, both genetically and morphologically to parent plant.
Vegetative propagation occurs through vegetative plant parts. In non-vascular plants, the vegetative reproductive parts are gemmae and spores whereas, in vascular plants, the roots, stems, leaves, and nodes are the parts that are involved in the propagation.
We have learned about the meristem tissue in plants. The same tissue also helps in the vegetative propagation. This tissue has undifferentiated cells which divide paving way for growth of the plant. Specialised permanent tissues are formed from the meristems.
Uses of Vegetative Propagation
There are mainly four uses of vegetative propagation:-
- The establishment of clonal banks.
- Mass propagation of selected materials.
- The establishment of clonal seed orchards.
- The propagation of special breeding materials. e.g. exceptional hybrids that are lost through sexual reproduction, sterile hybrids.
Types of Vegetative Propagation
In this process, the new plants grow out of the modified roots called tubers. Some plant roots develop adventitious buds. These buds grow and form the new plants/sprouts under the right conditions. These sprouts can be separated from the parent plant and when planted in other areas, the new plants are formed.
Example – Sweet potato, Dahlia etc.
Plants like Bryophyllum, Begonia etc., have adventitious buds whichcoming out from the notches of the leaves. These buds are develop into new plants.
Vegetative propagation occurs through the stems when new plants arise from the nodes. This is where buds are formed, which grow into the new plants. Stems that grow horizontally on ground are called runners. As these runners grow, buds are formed at the nodes, which later develop roots and shoots, resulting in the formation of new plant.
Example – Cyanodon; Mint etc.
The round, swollen part of underground stem is called a bulb. Within the bulb lies the organ for vegetative propagation such as central shoot that grows into a new plant. Bulbs have a bud surrounded by the layers of fleshy leaves.
Eamples include Onions, Garlic, and Tulips etc.
Stem tubers are found in plants like potatoes. This part is swollen apical part containing many nodes or eyes. Every eye has buds and new plants originate from these buds.
Cutting is the most common method employed by gardeners to grow new plants. A part of the stem is cut and planted in the soil, which develops roots and further grows into a new plant.
In grafting, two closely related plants are used to produce a new plant that has the desired, combined traits of both parent plants. One plant is the stock, where the root system is taken and other is the Scion, where the shoot system is used. The scion is attached to the stock of second plant in this method of artificial vegetative propagation. Grafting method is used in a variety of plants like roses, apples, avocado etc.
In the budding method, a bud with a small portion of bark is taken from the desired plant. This is inserted into a small slit that is made in the bark of other plant. Both the plants are tied together and buds are not allowed to dry. This will help them to produce.
Advantages of vegetative propagation
The main advantage of vegetative propagation methods is that the new plants contains the genetic material of only one parent, so that they are essentially clones of the parent plant.
This means that, once a plant with desirable traits, we can reproduce the same traits indefinitely, as long as the growing conditions remains similar. This is very important for commercial growers whoever wants to reproduce the highest-quality plants and ensure consistency of a variety of plant or crop for selling purpose.
This can also help to maintain consistent quality and taste of products made from plants or crops.
For example, in Zealong’s tea plantation, they propagate new tea plants by using cuttings, to ensure consistency in the taste and quality of their tea.
With vegetative propagation, plants also bypass the immature seedling phase and therefore they reach the mature phase very soon. This can save a lot of time and money for the commercial plant production.
For example, it takes 3½–4½ years for a tea plant to grow big enough to harvesting and processing into tea. Growing from seed would take even more longer.
Disadvantages of vegetative propagation
The main disadvantage is the potential to impact on biodiversity of the species. And if a particular plant clone is susceptible to certain diseases, there is the potential to lose entire crops, such as impact of kiwifruit disease Psa. One way to protect against these problems is to establish a genetic bank of seeds or plants, which is commonly practice in the various cropral sectors.