plant science. which of the following plants do you think would be easier to propagate using the...
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Herbaceous Cuttings
Plant Science
Which of the following plants do you think would be easier to propagate using the leaves?
Plant Propagation by Cuttings
Asexual propagation - the controlled reproduction of plants by taking a piece of vegetative plant tissue and encouraging it to regenerate a complete plant.
Sexual propagation - development of a new plant by meiosis & fertilization in the flower to producea viable embryo in a seed.
Totipotency – ability of a single cell to regenerate all characteristics of the plant.
Advantages of asexual propagation
Plants are uniform Quick establishment Only means of propagation in certain
species Seed-borne diseases avoided Less expensive Heterozygous material may be
propagated without genetic alteration
Disadvantages of asexual propagation
Systemic viral infection can spread to all plants
Planting materials are bulky Storage of asexual material is cumbersome
and short term All plants are genetically identical and
subject to the same hazards to the same degree
Mechanical propagation in some cases is not practical
4 Categories of Cuttings
Softwood cuttings – from soft, succulent, new spring growth of deciduous or evergreen species
Semi-hardwood cuttings – from woody, broad leaved evergreens, and leafy summer cuttings of deciduous plants with partially matured wood
Hardwood cuttings – from dormant woody material – taken in late winter or early spring before leaves appear – from previous year’s growth
Herbaceous cuttings – from succulent, non-woody plants, with leaves at upper end
Types of Herbaceous Cuttings
Definition of a cutting -Detached vegetative material from a plant used to produce a new plant.4 types:
Stem Leaf Leaf-bud Root
Stem Cuttings
2 types Stem-tip cuttings – tip (terminal end)
is cut and used to produce a seedling Stem-section cuttings – pieces of
stems containing at least one bud (not a terminal bud) and used to produce a seedling
Leaf cuttings
A whole leaf or part of one that is detached and used to raise a new plant.
Examples: begonia, peperomia, African violet
Cutting consists of leaf plus part of the leaf stalk (petiole)
Leaf-vein cuttings – cutting the veins at several points and
securing the leaf on the media
Leaf-bud cuttings
Consists of a short piece of a leaf, petiole, and short piece of stem with an attached bud in the leaf axil.
Great when source material is scarce.
Root cuttings
Small sections of the roots are divided and planted vertically or horizontally.
Proximal – nearest the crown of the plant – always should be up
Distal – farthest from the crown
Cuttings and Water uptake
Removed from functioning root system
There is little to no water uptake and can lose water to the air
Placing cuttings under a intermittent mist system provides water and high humidity
Adventitious roots New roots form in places that normally
do not grow roots (Ex: Stems, leaves)
Cultural requirements The tissue of the cuttings should contain
enough of the organic and inorganic nutrients to support new growth to the point of becoming self-supporting.
- Electric heating cables are commonly used to hold the medium at about 75F. Air temperature of 70-80F day and 60-70F night are generally satisfactory.
Light Requirements
The presence or absence of light is generally not decisive in rooting, although light tends to inhibit root initiation.
The general practice is to use shading to decrease light intensity but not to exclude light.
Media
The rooting medium should be well aerated, hold sufficient moisture, and be easily sanitized.
Soil is generally a poor choice. Commonly used media include perlite, and various mixtures of sand, peat, and vermiculite.
In this lab we will use a 1:3, Bark Mix :Perlite mix
Auxins
Auxins - a group of natural plant growth hormones, which can be applied directly to the cuttings.
Most commonly used compounds: synthetic auxins, indolebutyric acid (IBA), and napthaleneacetic acid (NAA).
Available in powder and liquid forms Rootone, Hormodin, Rhizapon & Dip ‘N
Grow.
Common Auxins
Indole 3- butyric acid (IBA) - Best for general use, non-toxic to plants over a wide concentration range
Napthaleneacetic acid (NAA)
Powder Formulations Vs Liquid Formulations of Rooting Hormones
Is Dip’ N Gro the Way to Go?
Liquid rooting hormone vs. powder formulations
Contains both IBA and NAA Dilution rates – versatility of product Absorbance into cutting vascular
system Alcohol incorporated into product –
sanitation Superior Performance
Auxin Forms Powder – Rhizapon, Hormodin, etc.
› Easy to use, but not as uniform› Not as effective as liquid auxins Pre-
drilling holes for sticking
Liquid - Dip ‘n Grow› Usually 3 to 5 second dip in solution› Dip as a bundle, not one by one› Majority of auxin is absorbed at the cut
surface of cutting base› Versatile
Depending of plant material, concentration levels are suggested:› Herbaceous & Softwood 1:20› Semi-hardwood 1:10› Hardwood 1:5
Dip time: 3-5 seconds› 5-second dip is equally effective as a 160-
second dip in promoting root growth. Longer dips, may cause phytotoxicity
Problem with auxins – they degrade in light
Powder formulations – once opened, subject to clumping
Liquid – 3 year shelf life if kept in a sealed container
Once diluted, 10 hour effectiveness
Another Issue: Auxins in Excess
Inhibit bud development
Cause yellowing and dropping of leaves
Blackening of the stem
Eventual death of cutting
Which should a grower use?
Other Methods of Application
Spray auxins to runoff over base of cutting
Cuttings stuck in media and auxin sprayed on leaves and stem until auxin drips in to media
Total immersion of cuttings - ivy, clematis, Ficus
Pre-Chemical Treatment of Cuttings
Treated with broad spectrum fungicidal dips prior to sticking
Sources for plant materials:
Outdoor landscape Greenhouse Annuals Houseplants Friends and Neighbors
Lab: Herbaceous Cuttings
- In addition to the different concentration levels, the length of time that the growth regulator remains in contact with the base of the cutting can also have an effect on rooting, which will be demonstrated in this laboratory project.
Materials Needed
Plant cuttings (to be designated) Propagation knife or razor blade Labels Pencil 1000 ppm IBA (Indole-3-butyric acid) and 500 ppm NAA (1-Naphthaleneacetic acid) Dip’ N Grow Dilution cup Propagation medium in flats-
1:3 Bark Mix : Perlite
Herbaceous Cuttings: Methods
Each group should prepare 12 uniform stem cuttings from the same genus, species and if applicable the same cultivar or variety and divide them into 4 equal groups.Re-cut the base of each group of cuttings and dip the base of each group into 1000 ppm IBA 500 ppm NAA (1:19 Dip N’ Grow : water) for the following time periods:
0 second- control 2 seconds 15 seconds 30 seconds
Any Questions??