propagation why we propagate plants.. why propagate? 1. ensure future generations. 2. keeps...
TRANSCRIPT
Propagation
Why we propagate plants.
Why propagate? Why propagate?
1. Ensure future generations.2. Keeps desired combination of traits
alive.3. Do not have to depend on seed
germination. Some plants have seeds that are hard to germinate. Also, do not have to worry about pollination.
Why propagate?
Possible Problems 1. Will not have genetic variation.2. Plants will not be able to change with
the surroundings.
Types of Propagation Two main types of propagation. They are:
Asexual and sexual.Asexual – cloning – does not require
fertilization1. Vegetative – reproduce by mitosis
(each daughter cell is an exact replica of it’s mother cell. (cont.)
Types of Propagation
Chromosome numbers and composition do not change during cell division). Ex: stolons and rhizomes.
2. Cuttings – taking parts of plants and planting them
Stem cuttingsLeaf cuttings
Stem Cutting with terminal growing area.
Stem Cutting
Leaf cutting with petiole.
Leaf cutting without petiole.
Leaf cutting that has rooted. Used leaf with petiole.
Leaf Cuttings
Leaf cutting with the petiole attached. Placed in water and will result in roots being formed.
Leaf cutting with petiole attached but placed in soil. This will be the result.
Leaf Cutting
Asexual CuttingsStem cuttings
Hardwood Semi-hardwood Soft woodHerbaceous
Leaf cuttingsLeaf-bud cuttings
Root Cuttings
Stem cutting with an auxiliary bud attached.
Stem cutting showing an adventitious bud starting. Begonia plant.
Stem Cuttings
Leaf Bud Propagation
For this type of propagation, you use a leaf and the axil of the leaf along with a portion of the stem. Place all of this into a medium and let grow. Type of plants you can use this on are: clematis, grape ivy, dracaena, camellia, jade plant and rhododendron.
Asexual Cuttings
3. Grafting – using woody stemsWhy do we graft?Things to remember when grafting.
Asexual Cuttings
3. Grafting – when grafting, you use some part of the woody stem. There are many types of grafts. The following pictures show a procedure called whip grafting.
Step 1 -Selection
Step 2 - Tools Step 3 - Cutting stem to make area for grafting.
Whip Grafting
Step 4 - Showing how to make the cut.
Step 5 – Adding the cut down through the middle.
Step 6 – Making the cut on the grafting material.
Step 7 – Making incision into the graft. Step 8 – Putting the
two grafts together.
Step 9 – Wrapping the graft.
Step 10 – Finished product.
Propagation Methods4. Budding – inserting bud into
existing wood5. Layering – taking a stem and
promoting root growth.
Layering – taking a branch and placing it on the soil.
Layering – Simple or mound
Removing epidermis for layering.
Air Layering
Packing moss around area to provide moisture.
Wrap in saran wrap to keep moisture in.
Removing saran wrap to see new roots and bud.
New bud with roots.
Separation Method
7. Separation – you take mature plants that were stolons or offspring from a parent plant and separate.
Runners
6. Runners – stems that run along the top of the ground. They root at the node.
Stolons – Parent plant puts out runners and each node a new plant forms along with roots.
Runners or Stolons
Separation of runner from parent.
Separation Method
Division
8. Division – taking tubers, roots, bulbs, or corms and dividing them.
Stem Tubers – potato – eyes become plants.
Stem Tubers
Division
Corms – roots develop around the edge in a circle. The enlarged area is the stem and the leaf sprouts in the concave area on top. Each one of these leaves will become a corm next year. Crocus and glads are examples.
Division
Suckering
Suckers – growth from the root or crown area. Would use division here because of the roots.
Suckering – where plants are produced from roots. Raspberries, willows and dog woods are examples.
Suckering
Tissue Cultures
9. Micro propagation – Tissue culturesTissue cultures are taking a small
part of a leaf or stem (usually cut into small pieces), placing them in a petri dish that contains agar (medium that has nutrients added to it).
Micro propagation – using a part of the plant such as a piece of the leaf (African violet) and placing it in a Petri dish that has agar in it. Roots form from this piece of leaf.
Micro propagation
Factors Influencing Rooting Factors influencing the rooting of cuttings.
1. Source of cutting material.Young, non flowering plants only a
few years away from a germinated seed is best.
2. Time of year the cutting material is taken.Woody perennial (means grows for a
number of years)- anytime
Factors Influencing Rooting
Hardwood cuttings – late winterSoftwood cuttings – spring after
growth reaches 4-6”.Semi-hardwood cuttings –
midsummerHerbaceous – anytime of the year
(do not develop woody tissues).
Factors Influencing Rooting
3. Treatment of cuttings with Auxins (natural plant hormones)IAA (indoleacetic acid), IBA
(indolebutric acid) or NAA (naphthalenoeacetic acid
All stimulate root growth
Factors Influencing Rooting4. Misting – needed in herbaceous
cuttings. Need to keep hydrated so will not dry out.Mist the plant then cover with plastic
cover. Keeps moisture in. Can also have an automated mist
system.5. Bottom heat – helps force rooting by
stimulating the root to grow.
Sexual Propagation
Seed formation is an example of sexual propagationGet genetic diversity from this formWhere you have a male and a female
and have cross pollination for fertilization between the two to form the seed.
Meiosis – another form of sexual propagation
Sexual PropagationIn meiosis the number of
chromosomes in the cells is reduced by half to form the male sperm cell and the female egg. The egg and sperm combine during fertilization in the ovule to form the zygote (fruit) that develops into the embryo (seed).
California desert plant called Machaeranthera gracilis example
Seed Germination
Monocot SeedThe seed imbibes (absorbs) water from
the soilEmergence of radicle (primary root) and
the plumule (primary shoot)These form the primary parts of the
plant.
Monocot Seed
Dicot Seed
Dicot SeedSeed imbibes water from soil and
swells.Radicle emerges and grows downward.Hook of the bean (hypocotyl) emerges
from soil, carrying the two cotyledons (leaves) with it.
Dicot Seed
Environmental Factors Influencing Seed Germination Adequate moisture in the soil. Proper temperature – cold versus warm Good aeration of soil. Light (in some cases) Freedom from pathogenic organisms.
Damping off. Freedom from toxic amounts of salts.