Transcript 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 Reproduction involving the exchange of genetic information, i.e. seeds and spores. Asexual Reproduction 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 When harvesting no longer impairs germination Storage Dry seeds Prevent excessive moisture Maximum dry weight Cool temps Rh + Temp < 100 When to sow seeds Seeding Direct sow Saves time and space Many cool season crops such as lettuce and spinach Transplant Improve germination Plants that mature slowly Plants with tap roots such as peas and radishes 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