Natural Vegetative Propagation

A plant carries on vegetative propagation at different stages of its life cycle. Nobody has to start it off, because it happens in nature by itself. A potato forgotten in the corner of a kitchen grows pale sprouts after a few days, and no one planted anything in it. A new banana shoot rises at the foot of the parent plant, and no one sowed a seed there. Reproduction that happens in nature from a plant's own vegetative parts is called natural vegetative propagation.

Natural vegetative propagation is of many kinds. It is found mostly in perennial plants, because a plant that lives on for years gets time to store plenty of food in its parts. Which part grows the new plant is not the same everywhere. It changes with the kind of plant and with its nature. Five parts do this work, and they are listed below.

• (a) Root
• (b) Underground stem
• (c) Aerial stem
• (d) Bulbil
• (e) Leaf

A root does not only pull in water and minerals. In plants such as rose, sissoo and guava, small buds sit on the roots themselves. If those roots get separated from the stem for some reason, the buds go on growing and develop a stem. In this way even a piece of root that has been carried away from the parent plant can become a whole new plant.

In plants such as asparagus, sweet potato and dahlia, the roots have stored a good amount of water and food. These roots develop a stem together with leaves. Roots then grow out from the base of that new stem, and it turns into a separate plant. The stored food is the new plant's own supply for its first days, which is why a sweet potato lying in soil can push out its first leaves without asking anything from outside.

Modified stems that lie under the ground are more capable of vegetative propagation. Being under the soil, they keep their stored food, they are safe from drying and from cold, and their buds stay protected. Such stems are of several kinds, namely the sucker, the rhizome, the corm, the bulb and the tuber.

In mint, water lettuce, banana, bamboo and ground raspberry, a rooted sucker comes out from the base of the aerial stem. These separate from the parent and become new plants. The young bamboo shoots seen pushing up in a bamboo clump are suckers of this kind.

The rhizome is a modified stem. It is found in ginger, turmeric, sweet flag and fern. A rhizome has a good store of food in it. A slender bud grows on it and a new plant is built up. If you look closely at a knob of ginger you can see small eye like buds, and it is exactly those buds that send up a green shoot once the ginger is put into soil.

The modified stem found in taro and gladiolus is called a corm. Buds come out from its knobs, and those buds make new plants. Around one taro corm there are usually several smaller corms, and each of them can give a plant of its own.

A bulb is a round stem. It is found in plants such as garlic, onion and tulip. Many new plants develop from a single bulb. If you break one head of garlic apart, you find many cloves inside it, and each clove gives a separate plant.

The underground stems of potato and yam are called tubers. They have eyes on them, and new plants sprout from those eyes. That is why a farmer planting potatoes chooses pieces that carry eyes. A piece with no eye gives no plant at all, however large it may be.

On the aerial stem of a plant there are slender buds at the nodes. In plants such as sugarcane and Bermuda grass, when a stem gets separated from the parent plant, the buds at the nodes go on growing, roots come out from the base of the bud, and it takes the form of a new plant. This is the reason sugarcane is planted by burying a piece of stem with nodes on it, laid flat in the soil, rather than by planting a whole plant.

In some plants a group of special buds forms at a node, at the edge of a leaf, or at the tip of the stem. Such a group is called a bulbil. Bulbils also form near the flower or above the fruit. Roots and shoots grow from a bulbil and a new plant is made. Pineapple, agave, sisal, lily, onion and garlic reproduce through bulbils. When a bulbil drops from the parent plant onto the soil, it takes root there and a new plant grows up.

In plants such as bryophyllum and begonia, once the leaf is mature, slender buds begin to sprout from the lamina, from the veins and from the notches along the edge of the leaf. Those buds grow on and build a stem with roots and leaves, making a new plant. When that leaf falls onto the soil, a good number of new plants start growing from it independently. Since a single leaf can give a dozen plants, bryophyllum spreads quickly.

Making your own collection of propagating parts is the surest way to learn what each part really looks like. For this you need a knife, plastic bags, cardboard paper and gum.

• Collect samples from different plants that show vegetative propagation from root, stem and leaf.
• Keep the collected samples in a room for a few days and let them dry.
• Press the dried samples, put them into small plastic bags and close the bags so that no air gets in.
• Paste the bags with the samples in them onto the cardboard paper in neat rows. The collection is ready.

Show the finished cardboard sheet in class, talk about what each sample shows, and then keep it safely in the laboratory.