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.