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3. Rhizomes:- The horizontal, thick and fleshy or slender and elongated stems growing underground are known as rhizomes. They have nodes and in tomodes and readily produced adventitious roots. Examples are banana, ginger ferns and many grasses.
4. Corms:- A corm is a solid-enlarged underground base of a stem having nodes and internodes. The gladiolus, crocus and water chestnut are examples of corm-forming plants. Several new small corms called cormels develop from the lower portion of the corm. These in turn are separated and when planted develop into new individuals.
5. Runners:- Runners are specialised aerial stems arising in the leaf axial of plants. The typical runner producing plant is strawberry.
6. Suckers:- Some plants such as pineapple, banana, etc, produce adventitious shoots from the underground portion of the stem or from their horizontal root systems. These are known as suckers and when they strike roots, they may be utilized as propagating material. ·
7. Offsets (or offshoots):- An offset is a shoot or thick stem arising from the base of the main stem of certain plants, such as date palm. They are girdled and layered for about a year before separation. PROPAGATION BY CUTTING
Many plants of horticulture interest are now propagated' commercially by means of cuttings, since it is the easiest and most convenient method of asexual propagation. A cutting is a part of a plant which will produce roots and, eventually, a new plant quite true to the parent plant. It may be a piece of stem (stem cutting), a leaf or part of a leaf, a piece of root (root cutting) or even a scale of a bulb. Stem cuttings are the most widely used. They are classified as : cuttings which require leaves and cuttings which do not require leaves at the time they are severed from the parent plant. Thus cutting may be classified as under:
1) Stem cuttings : Herbaceous cuttings usually consist of the terminal leafy portion of stems of herbaceous plants.
Softwood cuttings are usually with some leaves.
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JAIN BIOLOGY
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