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Biology

Vegetative Reproduction

Vegetative propagation involves the use of parts of plants in multiplying the plant or when a new plant grows out of a parent plant, without the use of seeds. Vegetative propagation involves two methods.

(i)Natural vegetative propagation: is carried out by plant themselves by means of leaves, stems and buds.

– leaves: tiny plants grow from the leaf which later break off to form a new plant. Bryophyllum and Begonia are good examples. In Bryophyllum and Begonia are good examples. In Bryophyllum the tiny plants grow from the veins at the end of the leaf margin while Begonia, they grow form the veins on the surface leaf.

– Stem: stems of different plants have modified themselves in different ways to carry out vegetative propagation. Some stems are modified as runners, rhizomes, corms and tubers.

– Runners: stem runners such as sweet potatoes grow horizontally along the ground

– Rhizomes: A rhizomes is a thick fleshy underground stem which grows more or less horizontally below the surface of the soil. Food is stored in the stem as starch. It has nodes and internodes. The scale leaves are membraneous and cover lateral bud at the modes e.g. canna lily and ginger.

– Corms: This is an underground stem which grows vertically in the soil. The stem is short and swollen with food reserve. Scale leaves, nodes, lateral buds are arranged over it while terminal bud is at the top. The new corm has adventitious and contractile roofs.

-Stem tuber: stem tubers have the terminal ends of their underground stems swollen with food reserve plants like yams and sweet potatoes which develop tubers. The underground stem tuber is left below in the non-growing season. The dormant underground tuber gives rise to another aerial shoot when rain return in the next growing season.

Sweet potato, the tuber has auxiliary buds covered with sale leaves.

– Suckers: suckers are underground young plants which develop from the axilliary buds of the parent plants. The terminal  buds of suckers grow above the soil to form shoot. Examples of plants that develop suckers of the base of their stems are plantain, banana and pineapple.

(i)         Bulb:

The shoot of some plants are modified to form underground buds for vegetative propagation. Example of bulb is onion, tulip and daffodil. Bulbs are underground compressed shoot or buds. The stem is very short with inner scale leaves which are fleshy and swollen with food reserves. They overlay and the out leaves are by dry, scaly and brownish terminal and lateral buds are parent. Adventitious root rise from the short stem.

(ii)Artificial vegetative propagation:

this is carried out by planting parts of perennating organs (organs that survive from one growing season to the next) like tubers and rhizomes. Each perennating part must possess a bud which can develop into a new plant

i.Budding: This is the bring together of the bud and stock. The bud and stock. The bud is taken from a tree already producing or matured. This forms the bud stock or slip the stock is a young plant of about a year old. During building, a T-shaped cut or inverted T in made at about 45cm from the ground on the stem of the stock plant. The cut shape is slight by raised to expose the cambium. The bud is carefully slipped into the raised bark and pressed formly to ensure that the cambia of both bud and stock unite together. It is commonly used in citrus to select desired species

  1. Layering: this involves bending shoot or branch of a plant to the ground so that the nodes can make contact with the soil. It is then pegged below the ground and covered with rich soil to provide good medium root development. When roots have emerged the branch is cut form the parent plant-layering can be used in coffee, cocoa and kola production

iii.Cutting: this involves the use of mature stem or branch to propagate plants. This is a very common method of asexual propagation in many crops such as cassava, croton and sugar-cane. The plant produced have the same character as the original plant from the cuttings were obtained. The cutting should be about 20cm long or convenient length with two or three nodes or buds. It should be put into ground to enable it have contact with the soil. It should be watered after planting or raised in shade during dry season or planted during the rain.

iv.Grafting:

this is the union of the stock and scion. The part of the plant whose root is in the ground is called the stock while the shoot removed from other plant is called scion. The two plants must be of the same species or closely related species. The plant should be of the same age and size for grafting to be possible. Both plants are cut in a slant or V-shape to provide good surfaces fro contact. They are then tied together with plastic tape or any device to keep them in place the junction is rubbed with grafting wax to prevent the entrance of air, water and pathogens

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