Notes of class 8

Artificial vegetative propagation :- Vegetative propagation in plants performed by human for economic benefit or for getting new variety is called artificial vegetative propagation.
Following methods are used for artificial vegetative propagation :-
(i) Cutting :- 

• In cutting method a small piece of stem (which bears buds ) from parent plant is cut and  put in the soil .
• The bud present on the node of that cut stem grow as a new plant.
• Since new plant is growing with the help of vegetative part ( stem ), it is called vegetative propagation.
• Example - Rose, Sugar cane etc.

(ii) Layering :- 

• Layering process is performed in shrub which has flexible stem.
• In layering process a flexible stem of shrub is bent and a part of it is put in the soil.
• After some time under ground part of stem start growing root and its shoot system grows upward.
• Now new plant should be separate from parent plant and new plant start its individual growth. 

(iii) Grafting :-

• Stock is the rooted part of graft.
• Scion is the aerial part of graft.
• In grafting method new variety is produced by mixing the desired features of two or more plants.
• Stock of one plant and scion of another plant are tied together and their vascular bundles (xylem and phloem) join after some times.
• New plant produced after grafting represent features of both plants.

(iv) Tissue culture :- 

• Explant :- A small piece of tissue cut from vegetative part of plant ( Stem, Root, Leaf ), used for the tissue culture is called explant.
• Antiseptic :- A chemical which prevent growth of micro organisms on living tissue is called antiseptic.
• Medium :- Medium is the solution of nutrient ( Minerals ) in which explant is kept for cell division.
• Callus :- The callus is mass of undifferentiated cells in the medium.
• Plantlet :- Callus is given command to develop root and shoot by using the phyto hormones in laboratory. Small growing root and shoot from callus make it the plantlet.

In tissue culture many plantlets can be produced at a time.

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About sexual reproduction in plant we will discuss in our next class............

Bye!