BIOLOGY [5 Mark Question Answer]

The methods by which plants can be vegetatively propagated artificially are
(i) Cutting - In this method, stems are cut into pieces and planted in the soil. This is the easiest and most frequently used method of artificially propagating plants, Eg. - Sugarcane, grapes, rose, etc.

(ii) Layering - Here, an intact branch is bent into the soil and is covered with moist soil. The growing tip remains above the soil. When roots arise in the branch region in contact with soil, it is separated from the parent plant. Within a few weeks, a new plant can be propagated by this method. Eg. - Cherry, jasmine, and grapevine

(iii) Grafting - Here a detached part of one plant called scion is inserted into the stem of a rooted plant called stock. Scion is a short piece of detached shoot containing several buds. Stock is the lower portion of the plant fixed in the soil. The scion is cut and placed face to face with stock. After a few days, a vascular connection is established between the joined parts and parenchyma tissue develops at the junction of the graft. Eg. - Apple, pear, mango, guava.

(iv) Budding - Here a single bud instead of a branch is grafted on the stock. In about two weeks, the bud unites with the stock after which the stock just above the bud is cut off. Eg. - Lemon and hibiscus

(i) Cutting - In this method, stems are cut into pieces and planted in the soil. This is the easiest and most frequently used method of artificially propagating plants, Eg. - Sugarcane, grapes, rose, etc.

(ii) Layering - Here, an intact branch is bent into the soil and is covered with moist soil. The growing tip remains above the soil. When roots arise in the branch region in contact with soil, it is separated from the parent plant. Within a few weeks, a new plant can be propagated by this method. Eg. - Cherry, jasmine, and grapevine

(iii) Grafting - Here a detached part of one plant called scion is inserted into the stem of a rooted plant called stock. Scion is a short piece of detached shoot containing several buds. Stock is the lower portion of the plant fixed in the soil. The scion is cut and placed face to face with stock. After a few days, a vascular connection is established between the joined parts and parenchyma tissue develops at the junction of the graft. Eg. - Apple, pear, mango, guava.

(iv) Budding - Here a single bud instead of a branch is grafted on the stock. In about two weeks, the bud unites with the stock after which the stock just above the bud is cut off. Eg. - Lemon and hibiscus

Plant hybridization is beneficial to us in the following ways:

1. It is useful in obtaining clones and genetic experimental plants.
2. It is a quick and convenient method.
3. Hybrid plants are stronger than either parent plant in general and have a higher yield.
4. Crop plants giving a much higher yield can be developed using this technique.
5. Plants resistant to diseases, pests and climatic factors can be produced by hybridization with desired plants or wild species.
6. The hybrid plants (especially ornamentals) have more colourful or fragrant flowers that enhance their commercial value.

Vegetative propagation is economically important in the following ways:

1. Vegetative propagation is helpful in the improvement of food crops, cash crops and ornamentals.
2. Plants raised through vegetative propagation are totally identical to the parent plants (clones) and are genetically similar.
3. Vegetative propagation is the only method to multiply those plants where seed formation does not occur.
4. This is a cheaper, convenient and rapid method of plant multiplication.
5. It is the only method of reproduction in plants like grapes, roses, Chrysanthemums, pineapples etc. which do not form viable seeds i.e. seeds do not germinate.