Artificial Methods of Vegetative Propagation in Plants - Practice Questions & MCQ

• In some plants, where vegetative reproduction by natural means is difficult to occur, special techniques can be used.
• The plant cells are more totipotent than animal cells. 
• So they can be made to reproduce vegetatively. 
• Thus all the techniques or methods which are carried out by human beings to produce plants vegetatively, are called artificial methods. 

1. Cutting:

• It is a simple method, in which a suitable part of stem or root is cut.
• It is planted in the soil, along with some nutrients. 
• This cut part soon develops new roots and develops into a new plant.
• Certain root promoting chemicals like IBA, NAA are used.
• Root cuttings are commonly used in plants like lemon, tamarind, Blackberry, and raspberry, etc. 
• Stem cuttings are very common in plants like Rose, Croton, Sugarcane, Tapioca, China rose, Bougainvillea, Lemon, Coffee, and Grape, etc.
• Leaf cuttings are also used to produce new offspring, in plants like Sansevieria.

2. Layering:

• In this method, a twig (branch) of a plant is bent down, below the level of the soil. This bent part is called a layer.
• A small incision is made in this layer (bent portion). Now the portion is covered with soil. Moisture is given at regular intervals.
• Soon this covered portion develops new roots and becomes separated (or can be cut) from the main body, giving rise to the new plant. 
• This plant then can be shifted to some new location.
• Layering is common in plants like-jasmine, Strawberry, Grapevine, and Cherry, etc.
• In mound layering, the shoot is cut and the left part is covered with soil. It develops a number of shoots. 
• The gootee or air layering involves the rooting of aerial stems while attached to the parent plant.
• The formation of adventitious roots during air layering is induced by various stem treatments. 
• These generally involve the girdling or wounding of a small part of the stem, resulting in the interruption of the downward movement of organic materials such as carbohydrates, auxin and other growth factors from the leaves and shoot tips. 
• These materials accumulate close to the treated area and induce rooting.

3. Grafting:

• It is the technique of joining parts of two different plants to form a composite plant.
• It can be done efficiently in those plants, which are closely related and have vascular cambium.
• One plant, which has a strong root system, is selected as stock or stump (basal part).
• The branch of the other plant (which is to be grafted) is selected as the scion. 
• Scion is usually selected from plants that have desired superior characters.
• Grafting is carried out commonly in plants like Mango, Guava, Apple, Rubber plant, Citrus, and Pear, etc.