Definition Vegetative Propagation In Plants
When the plant is growing vegetatively, any part of it, say root, stem, or leaf may get separated from this plant. If this separated part can grow into new individuals their it is called vegetative propagation in plants.
As described earlier no specialized reproductive units are produced in the process of vegetative propagation.
Types Of Vegetative Propagation In Plants
Several types of vegetative propagation are seen among the flowering plants depending on the part involved in the process.
This may occur under normal conditions or maybe induced artificially.
Natural Vegetative Propagation In Plants
Natural vegetative propagation happens when plants grow and develop naturally without human intervention.
An important ability that is key to enabling natural vegetative propagation in plants is the ability to develop adventitious roots.
Some tap or adventitious roots of sweet potato, Dahlia, etc. become thick, swollen due to the storage of food. The adventitious buds are borne on such structures.
The buds produce leafy shoots, called slips. When such roots with adventitious buds are planted in the soil, they produce new plants and thus, vegetative propagation occurs.
By stems :
The stems are efficient means of vegetative propagation. This may be of the following two types.
(a) Subaerial stems:
Subaerial stems may develop as lateral branches from the mother plant. This may break up from the parent plant and then, grow into new plants.
Example- Runners (Oxalis), sucker – (banana, Chrysanthemum), stolon (Jasmine), offset (Eichhornia)
(b) Underground Stems:
In certain plants, the underground stems become modified for the storage of food during the active phase of the growth.
Examples- The rhizome (Ginger), tuber (Potato), bulb (Onion), and corm (colocasia)
By leaves :
The fleshy succulent leaves of Bryophyllum bear adventitious buds in their notches located in the margins. When the leaves fall on moist soil, these buds develop into small plants completing the process of vegetative propagation.
Artificial Vegetative Propagation In Plants
Artificial vegetative propagation is a type of plant reproduction that involves human intervention. The most common types of artificial vegetative reproductive techniques include cutting, layering, grafting, suckering, and tissue culturing. These methods are employed by many farmers and horticulturists to produce healthier crops with more desirable qualities.
Farmers, gardeners, horticulturists have taken advantage of this type of propagation in plants. They have manipulated the process for their own benefit.
This is a very common method. Here a piece of the stem up to a suitable length is taken from the parent plant. This stem piece is called the cutting. It should have a few nodes and internodes.
The cutting is planted in moist soil with suitable nutrients. After some time, roots emerge from the nodes of the basal portions of the cuttings and the upper buds give rise to the shoot.
Example: The plants of China rose, sugar cane, Bougainvillea, etc are commonly grown by this method.
In this process, a detached part of one plant (i.e. twig or bud) is inserted into the stem or root system of another plant.
The former is called scion (a short piece of detached shoot containing several dormant buds), and the latter stock (the lower portion of the plant which is fixed to the soil by its root system).
The grafted portion is covered by grafting wax to avoid infection.
In layering, roots are artificially induced to grow on the branches before they are detached from the parent plant.
There are three types of layering :
- Serpentine layering
- Mound layering
- Air layering
Advantages of vegetative propagation in plants
The importance of plant propagation are
- Because vegetative propagation is a form of asexual reproduction, plants produced through this system are genetic clones of a parent plant. This uniformity has advantages and disadvantages.
- One advantage of vegetative propagation is that plants with favorable traits are repeatedly reproduced.
- Commercial crop growers can employ artificial vegetative propagation techniques to ensure advantageous qualities in their crops.
Disadvantages of vegetative propagation in plants
- A major disadvantage, however, of vegetative propagation is that it does not allow for any degree of genetic variation.
- Plants that are genetically identical are all susceptible to the same viruses and diseases and crops produced through this method are, therefore, easily wiped out.