O.S.U.E. Master Gardener Mahoning County Class of 2017
Bill Snyder March 14, 2017 Plant Sciences
Agriculture - study of plants in relaEon to field crop producEon.
Agronomy - science of crop management and includes the study of soils.
HorEculture - science of growing fruits, vegetables, flowers, and other ornamental plants.
Botany - science involving the study of all phases of plant life and growth. Divisions of Botany Plant Taxonomy - classificaEon and naming
Plant Anatomy - structure
Plant Morphology - origin and funcEon of plant parts
Plant Physiology - processes of plants.
Plant Pathology - diseases of plants
Plant Ecology and Geography - relaEonships of plants in bio-communiEes and physical distribuEon Plant ClassificaEon
Teminology Plant ClassificaEon Based on Woody or Herbaceous
Lilac Peony A Woody plant is a perennial tree Herbaceous perennial plants have or shrub. The stem remains above stems that die back to the ground ground during the winter. each year. Plant ClassificaEon Based on Life Cycle (Herbaceous)
Annuals Biennials Perennials Plant ClassificaEon Based on Life Cycle Annuals complete a full life cycle in one year.
Marigolds Snapdragons Zinnias Note for Lawns: Summer annual weeds complete growing season during spring and summer. e.g. crabgrass and spurge (Spring preemergence applicaEon) Winter annual weeds complete growing season during fall and winter. e.g. annual bluegrass and henbit (Fall preemergence applicaEon) Plant ClassificaEon Based on Life Cycle
Biennials complete a full life cycle in two years.
Sweet William Swiss Chard Hollyhocks Plant ClassificaEon Based on Life Cycle
Perennials live for many years, forming flowers and seeds each year. The above-ground parts may die back in winter, but re-grow in Spring.
Hosta Dahlia Forsythia Herbaceous Perennials Woody Perennial Plant ClassificaEon Based on Winter Leaf and Needle Loss Woody Perennial are classified as either Deciduous or Evergreen. Deciduous – lose Evergreen – keep leaves or needles in winter leaves or needles year-around
Maple Larch Spruce Rhododendron Plant ClassificaEon Based on Seed ProtecEon Seed Plants are classified as either angiosperms or gymnosperms.
Gymnosperms are woody, perennial, and with few excepEons evergreen. Their leaves may be fern-like, scale-like, strap-shaped, or needle shaped. This group is represented primarily by cone bearing trees (conifers) and palm-like plants. Members of this group are cypress, pine, cedars and yews. Angiosperms are a class of plants in which the mature seed is surrounded by fruit. Angiosperms are trees that have broad leaves that usually change color and die every autumn (e.g. oaks, maples and dogwoods). Some angiosperms hold their leaves during winter (e.g. rhododendron). Evergreen Angiosperms (rhododendron) Evergreen Angiosperms (rhododendron) Deciduous Gymnosperms
European larch
Larix decidua European larch Larix decidua
Plant ClassificaEon Based on Plant Growth PaZerns (angiosperms classified) Cotyledons = seed leaves
Monocotyledonous plants Dicotyledonous plants
Monocots Dicots Plant ClassificaEon Based on Plant Growth PaZerns Plant Cell Plant Structure/Anatomy
Roots Root Types
Root Structure
(cell differenEaEon)
(cell growth)
(cell division) Xylem - carry water dissolved minerals.
Phloem - carry food such as sugars.
cells become specific Essues such as epidermis, cortex, or vascular Essue. undifferenEated cells
cells increase in size through food and water absorpEon. As they grow, they push the root through the soil.
area of cell division and growth Root Cross SecEon Root Growth The following factors are important in root growth:
Roots in water-saturated soil do not grow well and ulEmately may die due to lack of oxygen.
Roots penetrate much deeper in loose, well-drained soil than in heavy, poorly drained soil.
A dense, compacted soil layer can restrict or terminate root growth
In addiEon to growing downward, roots grow laterally and ocen extend well beyond a plant's drip line.
Keep this extensive root system in mind when disturbing the soil around exisEng trees and shrubs. Root Hair with Mycelia
Mycorrhiza is a symbioEc associaEon between a fungus and the roots of a vascular plant. Mycorrhizae The fungi mycelia connect to the Eny tree root hairs and deliver nutrients to the trees roots. Since fungi are excepEonally good at breaking down complex molecules into simple ones, they increase the trees ability to gather nutrients.
For trees this is especially criEcal during the first few years of life. When the seedling tree first gets established, its need for water and nutrients is ocen greater than its Eny root system can produce
Garlic Mustard
Garlic mustard is a biennial, growing its first year as a seedling and flowering the subsequent year. It most ocen grows in the forest understory or along forest edges but is also able to invade undisturbed forest habitats. It tolerates low light levels and is adapted to take advantage of disturbed habitats such as trails, roadsides and areas where trees have been removed.
Garlic mustard reproduces only by seed. Most seeds germinate within the first or second year acer being produced but can remain viable in the soil seed bank for up to five years.
Individual plants produce up up to 7,900 seeds and grow to 3 to 4 feet in height. Garlic Mustard produces chemicals which suppress mycorrhizal fungi that most plants, including naEve forest trees, require for opEmum growth. Because seeds contained in the soil can germinate up to five years acer being produced, long-term removal is required to deplete the seed bank and allow recovery of mycorrhizae. Roots as Food Sweet Potatoes are swollen tuberous roots.
Carrots, Parsnips and Radishes are elongated taproots. Plant Structure/Anatomy
Stems Stems Terminology
Shoot: A young stem (1 year old or less) with leaves. Twig: A young stem (1 year old or less) that is in the dormant winter stage (has no leaves). Branch: A stem that is more than 1 year old, typically with lateral stems radiaEng from it. Trunk: A woody plant’s main stem. Stem Structure Stems as Vascular Tissue
Stems support buds and leaves and serve as conduits for carrying water, minerals, and food (product of photosynthesis).
The vascular system inside the stem forms a conEnuous pathway from the root, through the stem, and finally to the leaves.
Water and food products move through this vascular system. Stem Structure Stem Plumbing
Xylem tubes carry water dissolved minerals.
Phloem tubes carry food such as sugars.
Cambium is a layer of acEvely dividing cells that separates the xylem and phloem, producing new xylem and phloem cells. Tree Trunk Basics Bark Phloem Sugars / Carbohydrates flow Cambium down and up the tree through the Phloem
Cambium cells divide to become Phloem and Xylem Xylem
Water and nutrients flow up the tree through the Xylem
Graphic by Joe Boggs, OSU Extension Ring Porous Trees Bark Water is transported only through the Phloem current annual ring Cambium
Ash Ash Trees Black Locust Elm Xylem Hickory Honeylocust Oak
Graphic by Joe Boggs, OSU Extension Diffuse Porous Trees Bark Water is transported through several Phloem annual rings Cambium
Birch Beech Dogwood Xylem Maple Maple Trees Poplar Sycamore Spruces, Pines, Firs, Hemlock
Graphic by Joe Boggs, OSU Extension Stem Structure
Monocot Stem (disconEnuous) Woody Dicot Stem (conEnuous)
Resistant to 2,4-D Herbicide Killed by 2,4-D Herbicide
Herbaceous Dicot Stem (conEnuous) Auxin (Plant Growth Hormone)
2,4-D Herbicide Stem Structure
Monocot Stem (disconEnuous) Woody Dicot Stem (conEnuous)
Resistant to 2,4-D Herbicide Killed by 2,4-D Herbicide
Herbaceous Dicot Stem (conEnuous) Stem Nodes
A node is an area on a stem of great cellular acEvity and growth, where small buds develop into leaves, stems, or flowers. Stem ModificaEons Above Ground: Crowns, Spurs and Stolons (runners)
Stolons are fleshy or semiwoody, elongated, Spur are short, stubby, side stems that arise horizontal stems that ocen lie along the soil from a main stem. They are the fruit-bearing surface. Strawberry runners are stolons. stems on pear, apple, and cherry trees.
Crowns (e.g. strawberries) are compressed stems with leaves and flowers on short internodes. Stem ModificaEons Below Ground: Bulbs, Corms, Rhizomes and Tubers
Daffodil Bulbs Lily Bulb
Tunicate bulbs (e.g., daffodils and tulips) Nontunicate bulbs (e.g., lilies) do have a thin, papery covering, which not have this papery covering. They actually is a modified leaf. The covering are very suscepEble to damage and helps protect the bulb from damage drying out. during digging and from drying out once it is out of the soil. Stem ModificaEons Below Ground: Bulbs, Corms, Rhizomes and Tubers
Crocus Corm Gladiolus Corm
When a corm Corms like bulbs are composed of is cut in half it stem Essue, but they are not the same. is solid, but Corms are shaped like bulbs, but do when a true not contain fleshy scales. A corm is a bulb is cut in solid, swollen stem with dry, scale-like half it is made leaves. Gladiolus and crocuses produce up of layers. corms. Stem ModificaEons Below Ground: Bulbs, Corms, Rhizomes and Tubers
Iris Rhizomes
Rhizomes resemble stolons In potato tubers, the “eyes” because they grow are actually the stem’s horizontally from plant to nodes, and each eye plant, but underground in contains a cluster of buds. the case of rhizomes. Potato Tubers Stems as Food Potato tubers are fleshy Ginger rhizomes are underground stems. fleshy stems. Plant Structure/Anatomy
Leaves Leaf Structure Terminology If peOole is absent, the leaf blade is sessile or stalkless.
Depending on node condiEons, or axillary buds can leaf axil develop into stems or leaves. Absorb sunlight for sugar producEon through Photosynthesis Leaf Structure Leaf Blade Layers Protect against dehydraOon and disease
waxy cuOn
Amount increases with increased light intensity – prevent sunscald Leaf Structure Leaf Blade CuEn Layer Leaf Structure Leaf Blade Layers palisade mesophyll palisade parenchyma ground Essue
photosynthesis Phloem – dissolved sugar Xylem – water and minerals photosynthesis
(gate) (pore) Leaf FuncEon Stomata – regulate passage of CO2, O2 and H2O
Prevent dehydraEon and resulEng sunscald
Most stomata on lower epidermis Tomato Leaf – “colorized” electron micrograph Light Induced Potassium Pump
CO2 enters for photosynthesis Leaf VenaEon Leaf Type Leaf Arrangement Leaf ModificaEon Spines are modified leaves, sEpules, or parts of leaves. (Thorns are modified branches or stems.) (Prickles are more comparable to hairs)
Bull Thistle Spines
no sOpules = exsOpulate Spines are modified leaves, sEpules, or parts of leaves. (Thorns are modified branches or stems.) (Prickles are more comparable to hairs)
Citrus Thorn Rose Prickles Leaf ModificaEon
A tendril is a specialized stem, leaf or peEole with a threadlike shape that is used by climbing plants for support and aZachment, generally by twining around whatever it touches. Leaf ModificaEon Bracts are modified or specialized leaves, especially ones associated with a reproducEve structure such as a flower. Some bracts are brightly colored and serve the funcEon of aZracEng pollinators. Examples of this type of bract include Poinsela and Bougainvillea.
Euphorbia pulcherrima (poinsela) Bougainvillea glabra