SEXUAL AND ASEXUAL PROPAGATION Plant Propagation

SEXUAL AND ASEXUAL PROPAGATION

Plant Propagation

FLOWERS, SEEDS, AND SHOOTS

Plant Anatomy

Flower Parts

Dicot Seed

Plant Anatomy

Dicot Stem Cross Section

StolonStolon RhizomeRhizome

Stolon vs. Rhizome

Sexual ReproductionSexual ReproductionAsexual ReproductionAsexual Reproduction

Reproduction involving the exchange of genetic information, i.e. seeds and spores.

Reproduction without the exchange of genetic information resulting in an identical clone, i.e. cuttings and division.

Propagation

Propagating by Seeds

Seed harvesting and storage

When to sow

Seed treatments

Depth

Temperature

Media

Transplanting seedlings

Pathogens

Harvesting Harvesting StorageStorage

When harvesting no longer impairs germination

Maximum dry weight

Dry seeds

Prevent excessive moisture

Cool temps

Rh + Temp < 100

Seeds Collection and Storage

When to sow seeds

Direct sowDirect sow TransplantTransplant

Saves time and space

Many cool season crops such as lettuce and spinach

Plants with tap roots such as peas and radishes

Improve germination

Plants that mature slowly

Increase yield or promote flowering

Seeding

Seed Treatments for Germination

Scarification

Stratification

Soaking

Depth

Light requirements

Twice as deep as the size of the seed

Too shallow is better than too deep

Temperature

Some seeds need certain temperature cycles to break dormancy.

Some crops, such as eggplants, need temps in excess of 80 degrees

As a general rule, temperatures in the mid 60’s are ideal.

Bottom heat can accelerate germination and plant growth.

Media

Seed germination media should be fine, retain moisture, and drain readily.

Fafard Superfine Seed Germination Mix is a good choice.

Avoid media with coarse perlite and large pieces of bark.

Transplanting

Soil temps- plants can take up nutrients when soil temperatures are above 40, but soil temps of 50 for warm season vegetables and perennials is preferred.

Evaluate roots- transplant when roots and reached the side of the container and have started to turn down. Avoid letting transplants become pot bound.

Handle young seedling by their leaves only. It is very easy to crush a stem during transplanting.

Attempt to spread roots out so they are not bent.

Manage shock- maintain consistent moisture. If using fertilizer wait until at least 3 irrigations have occurred before fertilizing.

Pathogens and Pests

Damping off

Insects

Fungus

Animals

Asexual Propagation

Tissue Culture/Micro-propagation

Layering

Grafting/Budding

Division

Cuttings

Tissue Culture

Simple LayeringSimple Layering Air LayeringAir Layering

Layering

Whip and TongueWhip and Tongue BuddingBudding

Grafting

Division

Timing- typically right after flowering

Balance- maintain a balance between root and shoot

Manage shock- maintain consistent moisture until established.

Cuttings

Competence: Competent cells found in nodes or basal plate

Timing: Specific to every plant

Condition of stock plant: Disease and pest free. Usually active but not vigorous growth

Cone of Juvenility: Juvenile tissue roots easier. Can be important with hard to root species. Mature tissue fruit or flowers faster, important with grafting fruit trees.

Ripeness: Semi-ripe wood usually roots best

Auxin : Cytokinin

Media- well draining: retains moisture

Temperature- bottom heat will greatly increase rooting speed/

Humidity- maintain high humidity but not standing water in leaves.

Cone of Juvenility

Phytohormones: Auxin

Auxins root ‘em : Cytokinins shoot ‘em

Auxin is synthesized in small amounts in the apical meristem and then transported down the dark side of the plant.

Auxin is photosensitive.

There are numerous forms of synthetic auxin.

Phytohormones: Cytokinin

Cytokinin is synthesized in the roots and promotes cell division.

The relative amount of auxin to cytokinin are key to plants regulating growth.

Plant Anatomy

References

The Complete Book of Plant Propagation, Clark and Toogood, 1992

Plant Propagation: Principles and Practices, Hartmann and Kester, 1983

Seed Starter, Heffernan, 1996