BIOLOGY [2 Mark Question Answer]

In layering, 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. Examples of plants in which layering is carried out are cherry, jasmine and grapevine.

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. After a few days, vascular connection is established between the joined parts and parenchyma tissue develops at the junction of the graft. Examples of plants in which grafting is carried out are apple, pear, mango and guava.

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. Budding is usually done in rainy season. Budding is carried out in plants like lemon and hibiscus.

Plants propagated through stem cuttings are:

1. Blackberries
2. Cannabis
3. Grapes
4. Pineapple
5. Sugarcane

Plants propagated through root cuttings are:

1. Roses
2. Raspberries
3. Blackberries
4. Crabapple
5. Fig
6. Lilac

Micropropagation is a technique of propagating plants by culturing cells, tissues or organs. This technique uses a very small amount of the stock plant.

The objectives of plant hybridisation are:

1. Development of hybrid vigour
2. Accumulation of desired traits of two or more plants in a single hybrid.