Plant Propagation by Specialized Structures

1. Suckers:

• A sucker is a shoot which arises on a plant from below the ground
• The most precise use of this term is to designate a shoot which arises from an adventitious bud on root
• However, in practices, shoots, which arise from the vicinity of the crown are also referred to as suckers even though originating from the stem tissues
• The tendency to suckers is a characteristic possessed

2. Crowns:

• The term crown is used to designate the part of a plant stem at and below the surface of the ground from which new shoots are produced.
• Division of the crown is an important method of propagation and this division wills plants.
• E.g. African violet, strawberry by some plants and not other

3. Bulb:

• Bulbs are produced by monocotyledons plants in which the usual structure is modified for storage and reproduction
• A bulb is a specialized underground organ consisting a short, fleshy, unusually vertical stem axis, at apex a growing point and enclosed by thick flexi scales
• Bulb scales morphologically are the continuous sheathing leaf bases
• The outer scales are generally fleshy and contain reserve food material
• Bulvets or bulbils will be separated and used for propagation. E.g. onion and garlic

4. Corms:

• A corm is the swollen base of a stem axis enclosed by the dry, scale (in contrast to the bulb ) which is predominantly leaf scalds a corm is a solid stem structure with distinct nodes and internodes
• The bulk of the corm consist of storage tissue composed of parenchyma cells
• In the mature corm, the dry leaf bases persist at each of these nodes and enclose the corm
• This covering is known as the tunic and gives a protection against injury and water loss
• Propagation is dry forms which will develop on the corm. E.g. Gladiolus

5. Tubers (Stem Tubers):

• A stem tuber is the short terminal portion of an underground stem which has become thickened because of the accumulation of reserve food materials
• E.g. potato, propagation by tuber can be carried out either by planting the whole tubers or by cutting them into sections, each containing a bud or eye

6. Tuberous Roots (Root tubers):

• Certain herbaceous perennial produce thickened roots which contain large amount of stored food
• The tuberous roots differ from the tubers in that they lack nodes and internodes
• Adventitious buds are present only at stem and these fleshy roots are separated and used propagation

7. Rhizomes:

• A rhizome is a horizontal stem growing either underground or along the surface of the ground
• Typically, it is the main axis of the plant, producing roots on it lower surface and extends leaves and flowering shoots above the ground

• It may be thick and fleshy or slender and elongated but it is always made up of nodes and inters nodes
• E.g. Canna, Ginger, propagation by Rhizomes consist of cutting or dividing the rhizome into selection each of which is capable of producing new shoot (it should have nodes) from nodes and foods from adventitious buds of lower surface

8. Runners:

• A runner is specialized stem which develops from the axial of a leaf at the crown of a plant
• Grows horizontally along the ground and forms a new plant at one of the nodes
• E.g. strawberry, In propagating by runners the rooted daughter plant are dug when they have become well rooted and transplanted to the desired locations
• E.g. Sweet potato, Dahlia.

9. Stolen:

• Stolen is a term used to describe various types of horizontally growing stems that produce adventitious rots when comes in contact with the soil
• Specifically, these are prostrate stems as found in Bermuda grass (Cynoden dactyalon), the underground stem of the potato that terminal as in tuber is a stolen