Wednesday, Sept. 10 1.  Turn in Homework – 5 Questions (Will return first two

homework assignments on Monday) (3 minutes)

2.  Field Trip Forms – Go over for 9/25, discuss Monday (5)

3.  Self-Assessment – Discuss questions/grading (hw) (5)

4.  Homework for Monday – Hand out reading and assignments (5)

5.  Poinsettia Watchdogs – update on crop and refer to schedule (5)

6.  Asexual Propagation (15)

7.  Chapter 2 – (35)

Asexual (Vegetative) Propagation

Vegetative reproduction is defined as the production of new plants from the vegetative parts like leaf, stem, roots of the parent plant.

Why Use Asexual Propagation?

v  Uniformity

v  Propagate non-seed producing plants

v  Avoid seed-borne diseases

v  To create insect or disease resistant plants

v  To incorporate environmental tolerances

v  To reproduce and retain the genetic traits of a hybrid

v  Control size and form of a plant

v  Can be faster and easier, cheaper

Disadvantages of Asexual Propagation

v  Uniformity (may not be desired)

v  Short storage time (live cuttings)

v  Bulky (vs. seeds)

v  Systemic infections can be spread easily, as the plants are clones (genetically identical)

Types of Asexual Propagation

v  Specialized parts

v  Cuttings

v  Layering

v  Grafting

v  Tissue culture (micropropagation)

Specialized Plant Parts

v  Offshoots

v  Separation

v  Division

Division - Stolon

A potato is a stolon, an underground storage structure (stem). Nodes along the stem sprout stems, leaves, and roots.

Division - Rhizome

Rhizomes and stolons are underground stems.

Rhizome Division

Tuber Division Caladiums are tubers, another specialized stem structure.

Division of Many Perennials

Division – Fleshy Roots

Division – Tuberous Roots

Separation

v  Bulbs

v  Corms

Separation – Bulbs

Separation – Bulbs

Separation – Bulbs

v  Amaryllis (a tunicate bulb)

Separation – Scaly Bulbs

Separation - Corms

A corm is not a true bulb. To divide them, simply separate the new corms or cormels.

Yellow and browning leaf margins could indicate ammonium toxicity, but that is usually accompanied by interveinal chlorosis. A calcium deficiency deficiency would have young leaves chlorotic (yellowing and curling up) rather than the lower leaves. Ca is nonmobile so deficiency is shown in upper leaves. If soluble salts are too high, say, from the water,

Without a tissue analysis, it is hard to say for sure, but it could be a Mo deficiency. This could be corrected with a foliar spray. Were we a commercial greenhouse, we would do a tissue analysis. Today we will measure the pH and electrical conductivity/total dissolved solids (TDS). (First we will test the EC of the water.) We’ll do it again in Monday’s lab.

In a commercial greenhouse we would have done the water testing first. Another problem we have is whitefly, which sucks the juices out of the plants. We can treat them in the larval stage with Safer Soap, which we apply 1:50 with water after shaking the bottle. We spray it on the undersides of the leaves, especially, as that is where they feed. It smothers the nymphs and several other pests. We could also treat them by releasing lady beetles, minute pirate bugs, green lacewings or other predatory or parasitic predators.

Write in Your Greenhouse Notebook v  Potted rooted cuttings: 9/3/14

v  Added shade cloth: 9/3/14

v  Fertilized with 300 ppm 15-5-15 Cal-Mag fertilizer. (4.05 z. or 114.8 g/gal. conc.): 9/3/14

v  Treated with BanRot (recommended for poinsettias is 6-12 oz./100 gal.)

12 oz./100 gal=.12 oz/1 gal. x 16 (for the 1:16 proportioner) = 1.92 oz./gal. conc.: 9/3/14

v  Fertilized and treated with BanRot: 9/5/14

v  Removed dead leaves: 9/5/14, 9/8/14

v  Removed Shade Cloth: 9/8/14

v  Sprayed with Safer Soap: 9/8/14

v  Fertilized: 9/9/14

Tradescantia zebrina “wandering Jew” Spiderwort family Commelinaceae From southern Mexico, Honduras, Guatemala vine; stem cuttings

Philodendron cordatum “wandering Jew” Arum family Aracaeae Epiphyte from Southeastern Brazil vine; stem cuttings

Some plants we are propagating – 1. Herbaceous Vines

2. Succulent Leaf Cuttings Crassula ovata “jade plant” Crassulaceae Shrub from South Africa Leaf or stem cuttings

3. More Leaf Cuttings

Peperomia obovatus “baby rubber plant” Pepper family Piperaceae

Succulent epiphyte that grows on rotting wood in tropical and subtropical regions

Leaf or stem cuttings

“African violet” Saintpulia spp. Gesneriad Family Gesneriacae From tropical Africa Leaf cutting

4. Baby plantlets from runners (stems) Chlorophytum comosum ‘Variegata’ “variegated spider plant” Asparagus Family Asparagaceae Native to South Africa

The flowers

Epiphyllum oxypetalum “queen of the night” Cactus family Cactaceae Cuttings of phylloclades (modified branches) Epiphyte from Sri Lanka

Schlumbergera x buckleyi “Christmas cactus” Epiphyte from Brazil

6. Evergreen Shrub 7. Deciduous Shrub

Rhododendron x hybrid “red azalea” Heath family Ericaceae Semi-hardwood cutting – when stem is at partial maturity (somewhat woody), around August to mid-Sept. in Mass.

Salix integra ‘Hakuro-Nishiki’ “dappled Japanese willow” Williw family Salicaceae Softwood cuttings in spring or semi-hardwood to hardwood cuttings in fall or winter. Easy to propagate.

Stem Cuttings v  Herbaceous

v  Woody plants

v  Softwood

v  Semi-hardwood (ripe)

v  Hardwood

Herbaceous Cuttings

v  Stem

v  Stem tip

v  Leaf bud

v  Leaf Petiole à

Stem Cuttings v  Softwood – late spring,

new growth

v  Semi-hardwood (ripe) – summer, recent growth

v  Hardwood – late fall (dormant), 1 yr. growth

Roots tend to develop at nodes

node

Cutting principles v  Age of material

v  Correct seasonal timing

v  Sterile rooting medium, sanitation

v  High humidity

v  No direct sun

v  Shoots without flowers or flower buds

v  Node near base of cutting

v  Rooting hormones

v  Basal wounding of woody cuttings

v  Remove leaves in contact with rooting medium

Herbaceous Cuttings v  Herbaceous cuttings are made from non-woody,

herbaceous plants such as coleus, chrysanthemums, and dahlia.

v  A 3- to 5-inch piece of stem is cut from the parent plant. The leaves on the lower one-third to one-half of the stem are removed. A high percentage of the cuttings root, and they do so quickly.

Softwood Cuttings v  Softwood cuttings are prepared from soft, succulent,

new growth of woody plants, just as it begins to harden (mature). Shoots are suitable for making them when they can be snapped easily when bent and when they still have a gradation of leaf size (oldest leaves are mature while newest leaves are still small.)

v  For most woody plants, this stage occurs in May, June, or July. The soft shoots are tender, and extra care must be taken to keep them from drying out.

v  Successful with many deciduous and evergreen shrubs and trees.

Semi-Hardwood Cuttings v  Semi-hardwood cuttings are usually prepared from

partially mature wood of the current season’s growth, just after a flush of growth. This type of cutting normally is made from mid-July to early fall. The wood is reasonably firm and the leaves of mature size.

v  Many broadleaf evergreen shrubs and some conifers are propagated by this method.

Semi-hardwood (ripe) cuttings

Hardwood Cuttings v  Hardwood cuttings are taken from dormant, mature

stems in late fall, winter, or early spring. Plants generally are fully dormant with no obvious signs of active growth. The wood is firm and does not bend easily.

v  Hardwood cuttings are used most often for deciduous shrubs but can be used for many evergreens. Examples of plants propagated at the hardwood stage include forsythia, privet, fig, grape, and Spirea.

Procedures for Rooting Stem Cuttings

²  Cuttings should generally consist of the current or past season’s growth.

²  Avoid material with flower buds if possible. Remove any flowers and flower buds when preparing cuttings so the cutting’s energy can be used in producing new roots rather than flowers.

²  Take cuttings from healthy, disease-free plants, preferably from the upper part of the plant.

²  Avoid taking cuttings from plants that show symptoms of mineral nutrient deficiency or that have been fertilized heavily

²  The stock plant should not be under moisture stress. In general, cuttings taken from young plants root in higher percentages than cuttings taken from older, more mature plants. Cuttings from lateral shoots often root better than cuttings from terminal shoots.

Procedures for Rooting Stem Cuttings

²  Early morning is the best time to take cuttings, because the plant is fully turgid. Keep the cuttings cool and moist until they are stuck. If there will be a delay in sticking cuttings, store them in a plastic bag in a refrigerator.

²  Terminal parts of the stem are best, but a long shoot can be divided into several cuttings, generally 4 to 6” long. Use a sharp, thin-bladed pocket knife or sharp pruning shears. If necessary, dip the cutting tool in rubbing alcohol or a mixture of 1 part bleach to 9 parts water to prevent transmitting diseases from infected plant parts to healthy ones.

Procedures for Rooting Stem Cuttings

²  Remove the leaves from the lower one-third to one-half of the cutting. On large-leafed plants, the remaining leaves may be cut in half to reduce water loss and conserve space. Species difficult to root should be wounded by gently scraping the bark.

Procedures for Rooting Stem Cuttings

²  Treating cuttings with root-promoting compounds can stimulate rooting of some plants that might otherwise be difficult to root.

²  Prevent possible contamination of the entire supply of rooting hormone by putting some in a separate container before treating cuttings.

²  Any material that remains after treatment should be discarded and not returned to the original container. Be sure to tap the cuttings to remove excess hormone when using a powder formulation.

Using Rooting Hormones

Rooting Media ²  The rooting medium should be sterile, low in fertility,

and well-drained to provide sufficient aeration. It should also retain enough moisture so that watering does not have to be done too frequently. Materials commonly used are coarse sand, a mixture of one part peat and one part perlite (by volume), or one part peat and one part sand (by volume).

²  Vermiculite by itself is not recommended, because it compacts and tends to hold too much moisture.

²  Media should be watered while being used.

Sticking Cuttings ²  Insert cuttings 1/3 to 1/2 their length into the medium.

²  Maintain the vertical orientation of the stem (do not insert the cuttings upside down). Make sure the buds are pointed up.

²  Space cuttings just far enough apart to allow all leaves to receive sunlight. Water again after inserting the cuttings if the containers or frames are 3 or more inches in depth.

²  Cover the cuttings with plastic and place in indirect light. Avoid direct sun. Keep the medium moist until the cuttings have rooted. Rooting will be improved if the cuttings are misted on a regular basis.

v  Rooting time varies with the type of cutting, the species being rooted, and environmental conditions. Conifers require more time than broadleaf plants. Late fall or early winter is a good time to root conifers. Once rooted, they may be left in the rooting structure until spring.

v  Newly rooted cuttings should not be transplanted directly into the landscape. Instead, transplant them into containers or into a bed. Growing them to a larger size before transplanting to a permanent location will increase the chances for survival.

Rooting Time ²  Rooting time varies with the type of cutting, the

species being rooted, and environmental conditions. Conifers require more time than broadleaf plants. Late fall or early winter is a good time to root conifers. Once rooted, they may be left in the rooting structure until spring.

²  Newly rooted cuttings should not be transplanted directly into the landscape. Instead, transplant them into containers or into a bed. Growing them to a larger size before transplanting to a permanent location will increase the chances for survival.

v  .

Bottom heat aids in rooting

Good Sources on Plant Propagation For Further Reading §  Bryant, G. 1995. Propagation Handbook. Stackpole Books:

Mechanicsburg, Pennsylvania.

§  Dirr, M. A. and C. W. Heuser, Jr. 1987. The Reference Manual of Woody Plant Propagation: From Seed to Tissue Culture. Varsity Press: Athens, Georgia.

§  Hartmann, H. T., D. E. Kester, F. T. Davies and R. L. Geneve. 1996. Plant Propagation, Principles and Practices. 6th ed. Prentice Hall: Upper Saddle River, New Jersey.

§  McMillan Browse, P. D. A. 1978. Plant Propagation. Simon and Schuster: New York.

§  Toogood, A. 1993. Plant Propagation Made Easy. Timber Press: Portland, Oregon

Leaf Cuttings

Whole leaf (leaf-petiole) cuttings

Petiole à

Leaf cuttings

Keep moist at all times.

Leaf cuttings

Cuttings from Variegated Plants

Variegation may be due to a lack of pigment in an area, the masking of chlorophyll by other pigments, or the other pigments themselves, such as with shades of pink, red, and purple due to anthocyanin pigments. It may also be due to a virus.

Propagating variegated plants can bring about some surprises.

Runners

Layering

Types of layering v  Simple layering

v  Tip layering

v  Compound layering

v  Mound layering

v  Trench layering

v  Air layering

Tip layering v  Limited to brambles

Simple layering v  Layer in Spring with one-year-old wood –

v  rooted by fall--remove

Rooting layers

Compound (Serpentine) Layering v  Use with flexible vines

Mound Layering

v  Used for rootstock production in nursery trees

Trench Layering

Air Layering

v  Developed by the Chinese centuries ago

Air layering

Thanks to the wonders of grafting

Grafting

Why graft? v  Incorporate disease, insect resistance

v  Incorporate temperature tolerance

v  Quickly increase # of a desirable type

v  Change cultivar of fruit in an orchard

v  Control form (dwarfing, weeping, tree mums & roses)

v  Repair bark damage

Grafting principles

Contact between vascular cambium of scion and rootstock

Grafting principles v  Taxonomic compatibility

v  Timing of graft (dormant scion)

v  Waterproof graft junction

v  Rootstock diameter > scion diameter

Whip or Tongue grafting v  Most common grafting method

Grafting over v  Adding a cultivar to an established fruit tree

v  Replace the existing cultivar

v  Add a new pollinator

v  Try a new cultivar

v  Top-working

v  Frame-working

Bark grafting (rind graft)

Cleft grafting

Topworking

Double working v  Using an interstock to graft an incompatible scion to a

rootstock. The interstock is compatible with both scion and rootstock.

Side grafting

Approach grafting v  Use when detached scion not possible

Flat grafting cacti

Budding v  Scion is a bud

v  Used to propagate fruit trees, roses

T-budding Widely used for clonal propagation of temperate and tropical fruit trees and temperate ornamental shade trees.

Chip budding Chip budding is often used for fruit and ornamental, deciduous trees. Trees in the rose family such as apple, cherries, hawthorn, pear, plums and Sorbus are especially amenable to chip budding. Acers, Laburnum, Magnolia and Robinia are other trees frequently budded.

Patch budding

Patch budding is widely used in plants with thick bark that can be easily separated from the wood.

Bridge grafting to repair damage

Bridge graft to strengthen a narrow crotch angle

Inarching to repair damage

Micropropagation (Tissue Culture)

v  Utilizes cell and tissue culture

v  Home tissue culture