Reproduction in organisms — BIOLOGY STD 12 Science — Question

Artificial Vegetative Propagation:
Vegetative propagation can also be done artificially and the man-made methods for vegetative propagation are called artificial methods of vegetative propagation. They include:

1. Cutting: In this method, a small piece of any plant organ (stem, root or leaf) is used for propagation, e.g. leaves (Bryophyllum), roots (tamarind), stems (sugarcane, grapes, rose and Bougainvillea).
2. Layering: In this method, roots are artificially induced on branches of stem before they are detached from the parent plant, e.g.jasmine, grapevine, litchi, orange, etc.
3. Grafting: In this method, parts of the two plants are joined in such a way that they grow as one plant. The rooted supporting portion of one plant called stock, is joined with the twig of another plant called scion, e.g. rose, apple, plum, peach, mango, etc.
4. Micropropagation: This method includes propagation of plants by culturing the cells, tissues and organs in laboratory which is called tissue culture. Initially, this forms an undifferentiated mass of cells called callus. Later on, this callus differentiates to produce many small plantlets.

NOTE: Algae and fungi, though reproduce asexually but switch to sexual methods just before onset of adverse conditions. Higher plants exhibit sexual as well as asexual modes of reproduction.