Transcript Vegetative Propagation

Vegetative Propagation
Development of plants from
Stem Cuttings
Introduction
• Cuttings can be taken from almost any part of
the stock plant (the original plant) to produce
new plants that are genetically identical.
• The actual method chosen depends on the
species of plant and time of year:
– Stem
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Softwood
Herbaceous
Semi – hardwood (evergreen)
Deciduous hardwood
– Leaf
– Roots
Steps in taking Softwood cuttings
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Softwood cuttings are taken from
the tips of shoots which are young
and green and where the stem is
still soft.
The cutting should be 5 – 10 cm
long
The lower leaves should be
removed to reduce lose of water
through transpiration sometimes it
is also necessary to reduce the
area of larger leaves as well.
The cut end should be dipped into
a rooting hormone (Seradix B
no.1, containing IBA indole-3butyric acid)
The cutting should then be
inserted into a rooting medium
and left in a humid environment.
Steps in taking Herbaceous
Cuttings
• Succulent, nonwoody plants
(Chrysanthemums, Carnations
etc.) may be propagated this
way
• A stem 8 – 13 cm long with or
without leaves
• The conditions required for
sucessful propagation are the
same as for softwood cuttings
• Bottom Heat (placing the pot
on a heating pad to warm the
rooting medium up to an
optimum 20 – 25 oC) will
stimulate root formation to be
initiated faster.
Steps in taking Semihardwood
Cuttings
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Woody, broadleaved evergreen
plants are propagated in this way
The stem should be 8 – 15 cm
long with lower leaves removed
(up to a 1/3 of the original surface
area)
The stem should be removed just
below a bud
A heel should be left on the cutting
to increase the surface area of the
cambium cells (growing and
dividing cells). This can be done
by pulling the stem downwards to
rip a little of the bark off the stock
plant
IBA, high humidity and bottom
heat enhance rooting
Steps in taking Deciduous Cuttings
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This method is suitable for deciduous or
narrow-leaved evergreen species such as
pines)
The length of the stem varies depending on
the species e.g. 20 cm for black currants to
3 m for poplar poles
At least 2 buds (nodes) must be on the stem
The material is usually taken from last
seasons growth during autumn (pruned
branches are often used)
The stem may be wounded by removing
bark from the just above the basal cutting (at
the bottom) to expose more cambium aids
root development
Dipping in a strong IBA powder such as
Seradix 3 is often required
The stems should be inserted into the
ground outside and do not require any
additional heat or increased humidity
because they do not have any leaves to lose
water from
Summary of Stem Cuttings
Type of cutting
Description
Season
propagated
Length of
cutting
Conditions
New, soft
succulent
woody
species
Spring to
summer
8 – 13 cm
High humidity, bottom
heat, rooting hormone
(Auxin such as IBA)
Herbaceous
Succulent
stems from
nonwoody
plants
Year round
8 – 13 cm
High humidity, bottom heat
Semi-hardwood
Partially mature
wood on
current
season’s
growth,
wood
plants
Late spring to
late
summer
8 – 15 cm
IBA, high humidity and
bottom heat. Cutting
should be “wounded”
to have a heel
Mature,
dormant,
woody
plants
Autumn to late
winter
Up to 3 m
A high concentrated IBA
application, planted
directly outside
Softwood
Deciduous
Steps in taking Root Cuttings
• This method is best carried out
on young stock plants during
winter
• It is not a common method but
can be used for Wisteria or
Ailanthus
• The polarity (which way is up)
is very important when planting
vertically. Usually the root
cutting is planted horizontally
just below the surface of the
rooting medium
• Bottom heat helps to develop
roots and shoots in a few
weeks
Leaf Cuttings 1
• The laminar (leaf blade) or petiole (stalk) may be
used to propagate a few varieties of plants
• African violets and begonias are propagated by
removing a single leaf (either the whole leaf or
part of the blade)
• Sansevieria (“mother-in-laws tongue”) leaves
may be sliced into sections
• Begonia rex leaves have their veins cut and laid
flat on the growing medium
Leaf Cuttings 2
• As the leaves have no roots, they must be
provided with a highly humid environment
and bottom heat is recommended
• The new plants develop from either the
end of the petiole or from the veins of the
blade depending on the method used
Physiology of Root and Shoot
Formation for Cuttings
• All cuttings go through similar physiological
developmental stages from the time of cutting to
weaning (when the cutting is removed from the
propagation area to an environment similar to
which it will be planted).
• Dedifferentiation is the early stage when
adventitious roots or buds form from
differentiated cells triggered to form new
meristematic cells.
The First Stage
Dedifferentiation this is when adventitious roots or buds form from
differentiated cells triggered to form new meristematic cells.
This occurs in the cambium cells.
The Second Stage
The formation of root initials from cells near the vascular bundles which
have become meristematic by dedifferentiation.
The Third Stage
Parenchyma cells form callus which develops behind the wounded
surface of thecutting to protect it from drying out and from pathogens.
The Fourth Stage
Development of the Root Primordia from the root initials.
The Fifth Stage
Growth and emergence of the adventitious roots through the outer
tissues and through the callus. Vascular tissue develops between
the root primordia and the cutting.
The Sixth Stage
The cutting is removed from the propagating area and hardened off or
weaned.