Plant Propagation

Plant Propagation Sexual and asexual propagation

Plant Anatomy Flowers, Seeds, and Shoots

Flower Parts

Dicot Seed

Plant Anatomy

Dicot Stem Cross Section

Stolon vs. Rhizome Stolon Rhizome

Propagation Sexual Reproduction Asexual 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.

Propagating by Seeds • Seed harvesting and storage • When to sow • Seed treatments • Depth • Temperature • Media • Transplanting seedlings • Pathogens

Seeds Collection and Storage Harvesting Storage • When harvesting no longer impairs germination • Maximum dry weight • Dry seeds • Prevent excessive moisture • Cool temps • Rh + Temp < 100

When to sow seeds

Seeding Direct sow Transplant • 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

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

Layering Simple Layering Air Layering

Grafting Whip and Tongue Budding

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

Plant Propagation