Download Propagation of Flowers and Ornamental Plants by Specialized

Propagation of Flowers and Ornamental Plants by Specialized Vegetative Structures
Compiled by: Md. Dulal Sarkar
Lecturer, Department of Horticulture
Sher-e-Bangla Agricultural University
A. Vegetative Propagation
Vegetative propagation is the perpetuation and multiplication of plants through different
vegetative plant organs like sucker, tuber, corm, runner, rhizome etc.
B. Specialized Vegetative Structures
B.1. Bulb
A bulb is a modified orthotropic underground stem consisting of basal plate (bottom of
bulb from which roots grow), a terminal bud and numerous scale leaves (swollen bases of
foliage leaves). Cluster of fibrous roots develops at the base and it has no distinct nodes or
internodes. The terminal bud grows into the aerial shoot and lateral buds develop into
bulblets. There are two types of bulbs.
B.1.1. Tunicate bulb: This type of bulb consists of concentric layers of tightly arranged
scales, the outermost layer being a dry, membranous protective layer.
B.1.2 Scaly bulb: Scaly or non-tunicate, bulb lack an outer dry protective membrane. The
scales are not tight but loose and can be removed individually from the bulb.
Examples: Daffodil, Hyacinth, Iris, Lily, Tuberose, Tulip etc.
Propagation: Each bulb consisting two or more bulblets where they are separated and
planted from which a new plant grows up.
B.2. Bulbil
Bulbil is a modification of vegetative bud or floral bud that forms in an axil or in place of
flowers. These appear at first as small nodule like buds, beginning near the bottom of the
stem and continuing up.
Examples: Lily, Agave, Wood sorrel etc.
Propagation: Bulbils can be harvested once when they matured and planted as a normal
bulb in the soil. In any case it sheds from the mother plant and grows up into a new
independent one.
B.3. Corm
Corms are short, swollen underground stem growing in the vertical direction. It is more or
less rounded in shape or often flattened from top to bottom. It bears one or more buds in
the axils of scale leaves and an optical bud. The optical bud will develop a new leafy
plant, while the buds in the scale leaves form new corms. The corm contains a basal plate,
growing point and lateral bud develop into cormel.
Examples: Amorphophallus, Colocasia, Crocus, Gladiolus etc.
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Propagation: Each corm produces new corms and cormels on old ones, which are used
for multiplication.
B.4. Crown
Crown is the part of a plant between stem and root from which new shoots arise and
adventitious roots develop along the base of the new shoots.
Examples: Bamboo, Lily, Sansevieria etc.
Propagation: Cut back to the crown in the early summer that increases the production of
shoots. It should be done at the beginning or end of the growing season.
B.5. Offset
An offset or offshoot is a short, more or less thickened, prostrate branch that develops
from the base of the main stem usually starting from an axillary bud. Apex turns up and
produces a tuft of leaves above and a cluster of roots below.
Examples: Cymbidium, Dendrobium, Water lettuce, Water hyacinth, Salvinia etc.
Propagation: Cutting the offset close to the main stem with a sharp knife which can be
planted and grown as independent plants. If it is well rooted it can be potted, if not the
shoot is placed in a favourable rooting medium.
B.6. Rhizome
Rhizomes are thickened, prostrate, swollen, underground modified stem, distinguished
from the root by the presence of distinct nodes and internodes. It has scaly leaves at the
nodes, a bud in the axil and a terminal bud. But it has no basal plate. The stem is branched
and usually grow horizontally just below or at the soil surface.
Examples: Anthurium, Calathea, Canna, Couch Grass, Ferns, Iris, Lily, Orchid etc.
Propagation: Cutting the rhizomes into sections and each piece has at least one bud or
eye. Each one will produce new plant.
B.7. Runner
Runner is a slender, elongated, prostrate, aerial stem with long internodes, creeping on the
ground, and rooting at the nodes.
Examples: Centella, Cynodon, Fern, Orchid, Marsilea, Spider plant, Wood sorrel etc.
Propagation: Cutting the runner into pieces with adventitious roots from lower surface of
nodal regions and each piece will produce new plant.
B.8. Stolon
Stolon is a slender, elongated, plagiotropic stem arise from the base of the underground
stem. It bends down on or into the ground and, then strikes roots and develops a bud at
each node which grows into a new plant.
Examples: Colocasia, Dracaena, Tecoma, Water dropwort etc.
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Propagation: The axillary branches that arise from the stem which is very close to the
surface of the ground and break off from the parent plant that develops new plants.
B.9. Sucker
Sucker is a creeping, slender, short, lateral adventitious shoot arise from the underground
part of stem. It grows obliquely upwards and gives rise to a leafy shoot or new plant. The
internodes are short. The sucker strikes roots at the base either before it separates from the
mother plant.
Examples: Dagger plant, Cherry blossom, Creeping thistle, Chrysanthemum, Ligustrum,
Peppermint, Rose, Tree of Heaven etc.
Propagation: Suckers are usually dug during the dormant season and detached from the
mother plants for multiplication.
B.10. Tuber
A much enlarged portion of an underground stem provided with buds on the sides
and tip. It grows horizontally and swells up at the apex due to accumulation of food. They
do not have basal plate but they have nodes and internodes. Eyes present at the nodes
consist of scaly leaf with an axillary bud.
Examples: Caladium, Jerusalem artichoke,Wood sorrel etc.
Propagation: Propagation can be done either by planting the whole tuber or cutting them
into pieces containing one or more eyes. Each piece with eye is able to form new plant.
B.11. Tuberous root
Tuberous root is a thick, fleshy underground modified root that stored food. Roots are
swollen at the centre and tapered towards the both ends. They do not have nodes,
internodes and axillary buds. It produces a number of adventitious shoot called slips.
Examples: Asparagus, Begonia, Dahlia, Mirabilis, Ruellia etc.
Propagation: The tuberous root should not be divided in storage but should be divided
into sections with eyes during planting.
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Fig. Bulb of Tuberose
Axil
Bulbil
Fig. Bulbil of Tiger lily
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Flowering shoot
New bud
Leaf base
Node
Basal plate
Roots
Fig. Corm of Gladiolus
Crown
Fig. Crown of Day lily
Offshoot
Fig. Offshoot of Dendrobium
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Fig. Rhizome of Iris
Leaf
Runner
Node
Roots
Fig. Runner of Wood sorrel
Stolon
Aerial leaf
Fig. Stolon of Colocasia
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Fig. Sucker of Chrysanthemum
Fig. Preparation of Caladium tuber for planting
Distal end
Portion of crown
Proximal end
Fig. Tuberous root of Dahlia
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