Vegetative propagation is an asexual method of reproduction. The reproduction by vegetative propagation occurs only in plants not in animals. In vegetative propagation, new plants are obtained or germinate from the part of old plants (like stems, roots and leaves), without the help of any reproductive organs like animals. Vegetative propagation usually involves the growth and development of one (or more) buds present in the old part of the plant to form a new plant. These buds are in the dormant state (inactive state) in the old part of the plant. When provided suitable conditions (like moisture, warmth,etc.), these buds grow to form new plants same as her parent. Please note that vegetative propagation is also called vegetative reproduction. Here is an example of the vegetative propagation (or vegetative reproduction) in grass.
It is a common observation that green grass plants spring up in dry fields after the rains. This happens due to vegetative propagation as follows : The fields have dry stems of the old grass plants all over them. These dry stems have buds which are in the inactive state or ambitionless state. By getting rain water, the buds present on dry grass stems get activated and grow to produce new grass plants. Thus, the green grass grows in the fields after rains from the dry, old stems of grass plants present in the fields, by the method of vegetative propagation.
Buds are present on the stems as well as the leaves of the Bryophyllum plant which can develop into new plants. So, Bryophyllum plants can be reproduced or regenerate by the process of vegetative propagation by using either a piece of its stem or its leaves. For example, if we plant a piece of the stem or leaves and buds of a Bryophyllum plant in the ground then the new plant grow from the leaves, stem and bud. This happens as follows : The leaves of a Bryophyllum plant have special type of buds in their margins (or edges) [see figure 2(a)]. These buds may get detached from the leaves, fall to the ground and then grow to produce new Bryophyllum plants. Sometimes even before a leaf drops off from a Bryophyllum plant, we can see new plantlets already growing on it [see figure 27(b)]. When such a mature leaf of the Bryophyllum plant falls on the ground, then each plantlet can grow into a new plants. Another plant called Begonia also reproduces by vegetative propagation through its leaves.
Money plant can also be grown by vegetative propagation by using a piece of its stem as follows : Cut a piece of stem of money plant in such a way that it contains at least one leaf on it (The point on stem where a leaf is attached is called a node). Dip one end of this stem in water. After a few days we will find that new roots appear at the point where leaf was attached. The piece of stem will grow into a new money plant. please not that if we cut the stem of money plant in between two leaves, then it will not grow into a new plant. This is because it does not have a growing point (here a node) in it.
We will now describe the vegetative propagation of plants by using tubers which are the modified, underground stems (or roots). A tuber is the thickened, underground stem (or root) of a plant which is swollen with stored food. The tuber has a number of ‘buds’ (called ‘eyes’). Each bud (or eye) of the tuber grows into a new plant when the old tuber is planted in the soil in the next growing season. There are mainly two types of tubers these are stem tubers and root tubers. Potato is a stem tuber whereas sweet potato is a root tuber. We will now describe how vegetative reproduction in potato takes place by using tuber.
Potato tuber is an underground stem of the potato plant. Potato can be used for the vegetative reproduction of potato plants. Each potato tuber can produce more than one plant either two or three. This happens as follows : A potato tuber has many buds (called eyes) on its body (see figure 28). These buds act as organs for vegetative reproduction. When a potato tuber is planted in the soil, then the various buds of the potato tuber start growing and forms new potato plants. In figure 28, we have shown the new potato plants growing from only two birds of the potato tuber. Other Buds can also do the same.
Please not that it is not necessary to plant the whole potato tuber in the ground to produce new potato plants. We can even plant ‘cut pieces’ of a potato tuber in the ground to obtain new potato plants. But all these cut pieces of potato tuber should have a bud (or eye) on them if they do not have a bud or eye then the new potato plant was not grow. So, if we cut a potato tuber into a number of pieces in such a way that every piece has a bud (or eye) on it and plant them in the ground, then each cut piece of potato tuber will produce a new potato plant in due course of time.
Each potato plant produces more than one tuber and each tuber has more than one bud (which produce more than one new plant). Due to this, the vegetative propagation method of producing potato plants by tubers is much faster than the production of potato plants from seeds.
We can study the vegetative propagation of potatoes as follows : Take a potato and cut it into small pieces in such a way that some pieces contain a bud (or eye) in them. Place the potato pieces having Buds on wet cotton kept in a tray. Keep the tray aside for a few days (but Sprinkle water on the cotton daily to keep it wet). We will see that green shoots and roots appear from the buds of the potato pieces. These are the new potato plants. If, we take potato Pieces that do not have a buds in this experiment, then no new potato plants will grow from them.
The roots of a guava plant have Buds which can develop into new guava plants. In fact, a large number of plants can be reproduced by the method of vegetative propagation. Some of the examples of the plants which can be reproduced by vegetative propagation are : Bryophyllum, Guava, Potato, Onion, Banana, Garlic, Water hyacinth, Tulip, Mint, Strawberry and Lily.