Sexual Propagation Mr Wilson Uintah High School Objectives

Sexual Propagation Mr. Wilson Uintah High School

Objectives Students will describe the elements of propagation and the techniques and practices used for propagation. Define Propagation. List the two main types of plant propagation. Define germination. Identify the life cycle of plants. Identify the parts of a seed.

Objectives Continued Define seed dormancy. Explain why some seeds will not germinate right after ripening. Define scarification. Identify the factors affecting germination.

Objectives Continued Identify germination media requirements and components. Explain the ideal germination environment. Identify the proper steps in transplanting a seedling.

What is plant propagation? Plant propagation is reproducing, or increasing the number of plants. Either sexually or asexually.

What is sexual reproduction? Sexual propagation requires the union of the pollen (the male sex cell) and the egg (the female sex cell). n The union of the female and male sex cells to produce a seed (embryo). Ovule: female sex cell. Pollen: male sex cell. Embryo (seed-germ): an immature plant. n *Sexual reproduction involves the creation of a genetically new individual.

List and explain the different types of seeds. Monocots: n Seeds with one seed leaf. Leaves have parallel veins. 1 solid seed. Stem vascular bundles scattered. Roots are adventitious Flowers in multiples of three. Pollen with single furrow or pore

Dicots Seeds with 2 seed leaves or 2 cotyledons Veins are “webbed. ” Pollen with three furrows or pores. Flowers parts in multiples of four or five. Stem vascular bundles in a ring.

Monocots

Dicot Leaf

Dicot

List and explain the different types of flowers. Complete Incomplete

Complete Flowers Have all four major parts; sepals, petals, stamen and pistil.

Complete Flowers Sepals The outer part of the flower. n In open flowers, the sepals are found at the base of the plant.

Petals The brightly colored, soft tissue that attracts insects.

Stamens The male part of the flower that has an anther at the end of it to produce pollen.

Stigma n Pistil The opening of the pistil. Style n The tube-like structure that connects the stigma and ovary. Ovary n The site of fertilization and growth of the seed.

Stigma, Style & Ovary

Ovary

Complete Flower

Complete Flower

Incomplete Flower An incomplete flower is one that lacks one or more of the four principal components identified in a complete flower.

Explain the difference between a perfect and imperfect flower A perfect flower is one with both the stamen and pistil An imperfect flower is one that lacks one of the sex organs.

Define pollination, fertilization and germination. Pollination n The transfer of pollen from an anther to a stigma of a flower of the same species. Fertilization n The union of the pollen and ovule cells. Germination n The sprouting of a seed.

What are the parts of a seed? Seed coat - protective covering around the seed. Hard surface that protects the interior of a plant. Comprised of two coats n Testa: outer layer Embryo - The new plant that has developed as a result of fertilization. During germination it extends its roots and seed leaves to form a new plant. Endosperm - provide energy for embryo and young plant. It supplies enough energy for the plant to grow until the leaves start to produce energy.

What are the parts of a seed?

For what reasons are plants produced from seed? May be the only way to reproduce certain plants Only way to produce new varieties Sometimes less expensive than other methods Sometimes quicker than other methods Only way to attain plants with hybrid vigor

What are the characteristics of quality seed? Viable – ALIVE! Taken from strong healthy parent plants Collected and handled correctly

What are the sources for seed? Collect seed from local plants. Order seed from suppliers Utah and Federal Seed Acts Seed laws to protect consumers n Seed test dates, viability, germination, purity Note – Always buy seed from a reputable source! n

Direct seeding vs. Indirect seeding Direct seeding - seed is sown directly into the container (or ground) in which it will be grown. Indirect seeding - seed is sown into one container and later transplanted into a larger container or planted in the ground.

How do I plant a seed? Fill container with a quality growing media Moisten growing media Make a depression or hole into which the seed can be sown. Place seed into hole/depression. Cover seed if needed. Make sure soil Temperature is warm enough. General rule of thumb - Plant seed at a depth of 1. 5 times its length and cover if needed. Note: some plants seed is best planted on top of the soil – check seed label for planting information!

How do I plant a seed? Continued Label flat n Date planted n Species and variety n Name Water Place in germination conditions Transplant (if needed)

Define germination Germination: the development of a seed from a resting stage to a stage of growth.

Stages of Germination

Define seed dormancy Seed Dormancy: n A protective condition that prevents the seed from germinating until all of the environmental factors required for optimum growth are present.

Explain why some seeds will not germinate right after ripening Some seed coats are too thick or extremely hard to allow moisture into the embryo. Some seed coats contain a chemical inhibitor that must be washed away.

Define Scarification & stratification Scarification: n The scratching or removal of the seed coat to induce germination. Sandpaper Removal of an end of the seed Create a crack in the seed Soak in sulfuric acid n n n Must be washed several times after soaking in sulfuric acid. Dried Stratification – putting seeds in moist cold conditions to stimulate germination.

Identify the factors affecting germination Water absorption n n The seed does not need to be submerged in water, just moist. The water softens the seed coat. Causes the embryo to release the hormone gibberlin. Gibberlin activates digestive enzymes that cause the release of cytokins & auxins. Cytokins and auxins induce cell elongation and cell division.

Identify the factors affecting germination Continued Oxygen Supply n Needed for respiration

Temperature n Minimum: point at which seed will not germinate 32 -39 n Optimum: desired level for most species 68 -86 n Maximum: point at which seeds will not germinate 113 -120

Light n n Affects germination 4 types of light responsive plants Full light Half light/ half dark Full darkness No affect either way

Identify germination media requirements and components Requirements n n Not too heavy Contain small amount of nutrients for plant growth Free of all pathogens or weeds Holds water, but allows aeration and drainage (porosity) components

Explain the ideal germination environment Aeration n n Must have enough air for respiration If the soil is too hard (no pore space), water retention will be dramatically reduced

Temperature n n n Plants have an optimum temperature for growth Bottom heat (5 -10 higher than the air temperature) helps expedite germination Heat should be removed once germination occurs because the plants become too succulent (soft) and “leggy” and does not transplant well.

Moisture n n Too much water causes the plant to rot. Too light water causes the plant to dry out and die. Water drives many of the reactions in the plant. n Photosynthesis, respiration, nutrient uptake and nutrient transport

Intermittent Low-Pressure Misting n Controlled by a Time clock Solar-activated counter Electronic leaf Sub irrigation n Seed flats are soaked with water from the bottom. * Applied only during daylight hours because of disease and lower temperature caused by evaporative cooling of the water

Light n n Red wavelengths have the most influence on germination Far-red light becomes “leggy”

Germination Activity Acquire seeds that you want to test. Count out 100 seeds. Gather two paper towels and moisten them. Place the seeds, spread out on one towel, cover with the other towel and then roll up into rag doll. Place rag doll in plastic bag Label bag with your name and date. Place in greenhouse.

Protective coverings for young plants.

Plant Propagation – Asexual Propagation Mr. Wilson Uintah High School Agricultural Sciences

Asexual Example

What is asexual propagation? Reproducing plant by means other than seed. Asexual Reproduction: n n n The reproduction of a plant without the uniting of a pollen and ovule. Asexual reproduction is often referred to as vegetative propagation since no seed is involved. It is known as a clone (Produces a genetically identical plant). n Leaves, stems or roots may be used to grow a new plant.

What are the reasons for producing plant asexually? The only way to reproduce certain varieties. Assures that certain characteristics from the parent plant are carried to the next generation. Quicker than other methods. Less expensive than other methods.

What are the types of asexual propagation? Cuttings - using the stems and leaves to reproduce plants Division/Separation - pulling or cutting apart groups of plants to make new individuals Layering - producing a plant from a part of a plant while that part is still on the parent plant Grafting & Budding - connecting two pieces of living plant material together to form a single plant. Plant Tissue Culture - a collection of techniques used to maintain or grow plant cells, tissues or organs under sterile conditions.

Plant Propagation – Cuttings

Leaf Cuttings Leaf cuttings are used almost exclusively for a few indoor plants. Leaves of most plants will either produce a few roots but no plant, or just decay. Whole Leaf with Petiole Whole Leaf without Petiole Leaf Cuttings Whole Leaf with Petiole Detach the leaf and up to 1 1/2 inches of petiole. Insert the lower end of the petiole into the medium. One or more new plants will form at the base of the petiole. The leaf may be severed from the new plants when they have their own roots, and the petiole reused. Whole Leaf without Petiole This is used for plants with sessile leaves. Insert the cutting vertically into the medium. A new plant will form from the axillary bud. The leaf may be removed when the new plant has its own roots.

New adventitious shoots forming from African violet petioles inserted into the medium.

Other leaf cuttings Split Vein Split Vein Detach a leaf from the stock plant. Slit its veins on the lower leaf surface. Lay the cutting, lower side down, on the medium. New plants will form at each cut. If the leaf tends to curl up, hold it in place by covering the margins with the rooting medium.

Leaf Section Leaf Sections This method is frequently used with snake plant and fibrous rooted begonias. Cut begonia leaves into wedges with at least one vein. Lay leaves flat on the medium. A new plant will arise at the vein. Cut snake plant leaves into 2 -inch sections. Consistently make the lower cut slanted and the upper cut straight so you can tell which is the top. Insert the cutting vertically. Roots will form fairly soon, and eventually a new plant will appear at the base of the cutting. These and other succulent cuttings will rot if kept too moist.

Root Cuttings Root cuttings are usually taken from 2 to 3 year old plants during their dormant season when they have a large carbohydrate supply. Raspberry root cuttings. Suitable plants are: lilac, raspberries, perennial phlox, blackberries, gypsophila, and horseradish. Take root cuttings in autumn or spring to avoid disturbing the root’s growth. The roots also contain more stored food at this time. This helps the cuttings to grow. How to take and plant the root cuttings • Expose the roots of the parent plant. Cut roots of about pencil thickness. • Cut the roots into sections 25– 150 mm long. • Cut the top of each section square and the base with a slant. • Place them in the growing medium, either vertically or horizontally. • Put them on a hot bed or in a warm place. • Keep them well-watered.

What is a stem cutting? A section of stem with leaves attached. Should have three to four leaves for best rooting.

Stem Cuttings Numerous plant species are propagated by stem cuttings. Some can be taken at any time of the year, but stem cuttings of many woody plants must be taken in the fall or in the dormant season. Stem Cuttings Tip Cuttings Detach a 2 to 6 -inch piece of stem, including the terminal bud. Make the cut just below a node. Remove lower leaves that would touch or be below the medium. Dip the stem in rooting hormone if desired. Gently tap the end of the cutting to remove excess hormone. Insert the cutting deeply enough into the media to support itself. At least one node must be below the surface.

Other Stem Cuttings Medial Cuttings Make the first cut just above a node, and the second cut just above a node 2 to 6 inches down the stem. Prepare and insert the cutting as you would a tip cutting. Be sure to position right side up. Axial buds are always above leaves. Cane Cuttings Cut cane-like stems into sections containing one or two eyes, or nodes. Dust ends with fungicide or activated charcoal. Allow to dry several hours. Lay horizontally with about half of the cutting below the media surface, eye facing upward. Cane cuttings are usually potted when roots and new shoots appear but new shoots from dracaena and croton are often cut off and re-rooted in sand.

Eye Cuttings Single Eye The eye refers to the node. This is used for plants with alternate leaves when space or stock material are limited. Cut the stem about 1/2 -inch above and 1/2 -inch below a node. Place cutting horizontally or vertically in the medium. Double Eye This is used for plants with opposite leaves when space or stock material is limited. Cut the stem about 1/2 -inch above and 1/2 -inch below the same node. Insert the cutting vertically in the medium with the node just touching the surface.

Heel Cutting Heel Cutting This method uses stock material with woody stems efficiently. Make a shield-shaped cut about halfway through the wood around a leaf and axial bud. Insert the shield horizontally into the medium.

Why is rooting hormone used? To induce root formation To increase number of roots To prevent root-rot.

Why do people transplant cuttings? To maximize growth. Most cuttings are planted in small pots or flats. After they develop enough roots they are transplanted into larger pots.

How do you properly transplant cuttings? After cuttings have developed a mass of roots they are ready to be transplanted. Great care should be used when removing the plants from the medium. Carefully remove the cutting. Grasp the top of the cutting with your left hand, slide the right hand under the cutting, and gently lift it from the medium. If there is excessive amounts of medium, gently shake the cutting. Plant it in the new pot. Make sure it is no deeper than it was planted in the propagation medium. If they are planted too deep, tender stem tissue is exposed to any diseases in the medium. Water thoroughly.

What is the proper rooting environment? Moisture -- Cuttings have no roots and must be kept moist until roots form. Above Ground Temperature – Varies with crop Below Ground Temperature -- Bottom heat 70 - 80 degrees according to crop Time

Plant Propagation – Separation and Division

What is separation? Separation is a method of propagation that occurs naturally in which reproductive organs of a plant detach from the parent plant to become new plants. They are bulbs or corms.

What is a bulb? A bulb is a plant structure that consists of layers or fleshy scales that overlap each other.

What are the types of bulbs? Laminate or tunicate bulbs n n Have dry membranous outer scales which protect it from rough handling and drying. Ex. = tulip Nontunicate or scaly n n These bulbs have no outer covers. Ex. = Lily

What is a corm? A corm is a very solid, compact stem with nodes and internodes. Corms reproduce by the development of small cormels. Corms are undifferentiated, uniform, and contain no rings when cut apart. Corms are stem tissue, modified and developed to store food. x. = Gladiolus.

What is division? Division is a method of propagation requiring the cutting and dividing of plants. Rhizomes, tubers, and tuberous roots are used in propagation by division.

What is a rhizome? A underground stem. It grows horizontally and produces roots on the bottom and stems on the top. n Ex. =Iris, Bermuda grass.

What is a tuber? A tuber is a swollen end of an underground side shoot or stem. All tubers have eyes which produce a separate plant as it sprouts. n Ex. = Irish potato

What is a tuberous root? They are thickened roots which contain large amounts of stored foods. They differ from tubers in that they are roots and have buds only at the stem end. Roots are produced at the opposite end. EX. = Sweet potato

Plant Propagation – Layering MR. Wilson Uintah High School

What is layering? Reproducing a plant from a part of the plant while that part is still connected to the parent plant.

Tip layering

What is simple layering? Where a branch from a parent plant is bent to the ground where it is partially covered at one point in the soil.

Tip Layering Tip Layering Dig a hole 3 to 4 inches deep. Insert the shoot tip and cover it with soil. The tip grows downward first, then bends sharply and grows upward. Roots form at the bend, and the recurved tip becomes a new plant. Remove the tip layer and plant it in the early spring or late fall. Examples: purple and black raspberries, trailing blackberries. Simple Layering Bend the stem to the ground. Cover part of it with soil, leaving the last 6 to 12 inches exposed. Bend the tip into a vertical position and stake in place. The sharp bend will often induce rooting, but wounding the lower side of the branch or loosening the bark by twisting the stem may help. Examples: rhododendron, honeysuckle. Compound Layering This method works for plants with flexible stems. Bend the stem to the rooting medium as for simple layering, but alternately cover and expose stem sections. Wound the lower side of the stem sections to be covered. Examples: heart-leaf philodendron, pothos.

Air Layering Air Layering Air layering is used to propagate some indoor plants with thick stems, or to rejuvenate them when they become leggy. Slit the stem just below a node. Pry the slit open with a toothpick. Surround the wound with wet unmilled sphagnum moss. Wrap plastic or foil around the sphagnum moss and tie in place. When roots pervade the moss, cut the plant off below the root ball. Examples: dumbcane, rubber tree.

What is air layering? A part of the plant stem is girdled and then surrounded by a moist growing medium in some type of enclosure. https: //www. youtube. com/watch? v=qvi. LR miqrs 8

Stolons or Runners Stolons and Runners A stolon is a horizontal, often fleshy stem that can root, then produce new shoots where it touches the medium. A runner is a slender stem that originates in a leaf axil and grows along the ground or downward from a hanging basket, producing a new plant at its tip. Plants that produce stolons or runners are propagated by severing the new plants from their parent stems. Plantlets at the tips of runners may be rooted while still attached to the parent, or detached and placed in a rooting medium. Examples: strawberry, spider plant.

Plant Propagation – Grafting and Budding

What is grafting? Grafting is a process by which two different plants are united so that they grow as one. The scion is the newly installed shoot or top of the plant. The rootstock is the seedling or plant used as the bottom half of the plant. It becomes the root system of the newly grafted plant.

Why is grafting used? Rapidly increases the number of desirable plants. Gives plants stronger, more diseaseresistant roots. To topwork a large tree. To insert a different variety on part of the limbs of the tree. To propagate plants that may be difficult to bud.

What are the requirements for successful grafting? Compatibility n The plants must be closely related to each other so the scion and stock are able to grow together. Scion wood n The scion wood should be one year old and of vigorous growth. Timing n Grafting is usually done when the stock and scion are dormant and have no leaves.

What are the requirements for successful grafting? Matching of tissue n The cambium layer of the two matched plant parts must come in close contact and be held tightly together. Waterproofing n n After the graft is made all cut surfaces must be covered with a waterproof material like grafting wax, plastic ties, or rubber ties. https: //www. youtube. com/watch ? v=by-ZAAY 4 G_4

Grafting Examples https: //www. youtube. com/watch? v=885 VG cc. Srvs https: //www. youtube. com/watch? v =by-ZAAY 4 G_4 https: //www. youtube. com/watch? v =q. Tt. Xm. BVsol. Y

What is budding? In budding a single bud is used instead of a scion like in grafting.

Why is budding used? More plants can be reproduced from the same amount of parent wood. Budding is accomplished more quickly. Budding can take place at different times than grafting can.

What are some rules to follow to keep newly propagated plants disease-free? Hoses are not to be put in direct contact with the ground. Keep greenhouse floor clean. Keep all benches clean of plant material and debris. After propagating plants, clean all equipment. Clean knives by washing off with water, and then dip in rubbing alcohol. Return equipment to proper storage place.

https: //www. youtube. com/watch? v=3 ZD 2 fi. Gb. Wzo

Methods Of A sexual Propagation cont… 1 - A portion of a plant containing a bud may be able to produce a shoot and root, such as stem cuttings, leaf-bud cuttings, and root cuttings.

METHODS OF ASEXUAL PROPAGATION CONT… 2 - A portion of the stem may be buried until roots form; then the connection with parent plant can be broken. This called ground layering.

Methods Of Asexual Propagation cont. . 3 - A section of stem may be wounded and covered with moist peat and black plastic covering. After roots form, the stem can be detached and planted. This is called air layering.

Methods Of Asexual Propagation (cont. . ) 4 - The goal of grafting is to connect or fit two tissues of living plant issue together in such as way that they will unite and subsequently behave as one plant.

Methods Of Asexual Propagation (cont. ) 5 - Budding is the place of a single detached bud upon the stock.