Basic Botany for Master Gardeners Mary E. Olien Green Spring Gardens
Topics for Discussion • Today • Plant Classification • Structure and function • Next Week • Flower structures • Basic physiology • Conditions for plant growth
Classification • By growth habit: woody vs. herbaceous • By use: ornamental vs. natural • By hardiness: hardy vs. tender • By growth habit: annual vs. perennial • By structures: flowers, leaves, stems
Woody Have lignin in their tissues Have cambial layer from which "rings" of xylem and phloem arise. Are usually not green beyond the first season Herbaceous Do not have lignin in their tissues, and are usually flexible Lack cambial layer to generate "rings" of vascular tissue Stems do not persist beyond on season Horticultural Classification
Woody Evergreen Keep leaves more than one season Leaves often have a waxy cuticle Horticultural Classification • Deciduous • Drop leaves in fall • Thin leaves that grow quickly • Have lignin in their tissues • Have cambial layer from which "rings" of xylem and phloem arise. • Are usually not green beyond the first season
Herbaceous Horticultural Classification • Annual • Complete lifecycle in one season • Have shallow root systems • Do not have lignin in their tissues, and are usually flexible • Lack cambial layer to generate "rings" of vascular tissue • Stems do not persist beyond on season • Biennial • Completes lifecycle in two seasons • Forms rosette of leaves in the fall, bloom in the spring • Perennial • Lives more than two seasons • Stems may die back, but roots survive
Plants Non-vascular Mosses, liverworts, hornworts Vascular Non-seed Plants Ferns, horsetails, whiskferns Seed Plants Gymnosperms Cycads, ginkgoes, conifers Angiosperms Monocots Grasses, bulbs, palms Dicots Generalized Plant Classification
Taxonomic Hierarchy Kingdom Division Class Order Family Genus Species Var., Form, Cv. • Other examples: • Bryophyta – mosses • Pteridophyta – ferns • Pinophyta – conifers
Taxonomic Hierarchy Kingdom Phylum Class Order Family Genus Species Var., Form, Cv. • Other examples: • Magnoliopsida – dicotyledons
Taxonomic Hierarchy Kingdom Phylum Class Order Family Genus Species Var., Form, Cv. • Other examples: • Iridaceae – Iris family • Poaceae – Grass family • Bromeliaceae – Bromeliad family
Taxonomic Hierarchy Kingdom Phylum Class Order Family Genus Species Var., Form, Cv. • Other examples in the lily family: • Allium – onion • Frittilaria – frittilaries • Hosta – hostas
Taxonomic Hierarchy Kingdom Phylum Class Order Family Genus Species Var., Form, Cv. • Other examples in the genus Lilium: • L. suprebum – turks cap lily • L. formosanum – formosa lily • L. longiflorum – Easter lily
Taxonomic Hierarchy Kingdom Phylum Class Order Family Genus Species Var., Form, Cv.
Common names are descriptive, but not precise. Scientific names are used in the trade and in the literature. Rohod Blue-eyed Grass Sysyrinchium angustifolium P. Mill. Rosebay, Great Laurel, White Rhododendron Rhododendron maximum, L. Naming Plants
Genus Cornus Cornus specific epithet florida L. variety or cultivar var. rubra ‘First Lady’ florida L. The Linnaean System Linnaeus is credited with our current binomial naming system. • Language is Latin • Two part name, genus and specific epithet. • Genus is capitalized and is usually a noun • Specific epithet is not capitalized, and is usually an adjective. • Plants are referred to by genus, but not by specific epithet. • Variety name, cultivar name and naming authority are part of the official name. • Ex: Cornus florida var. rubra L. Flowering Dogwood
Structure and Function • Roots • Stems • Leaves • Flowers • Seeds
Roots • Tap • Fibrous • Adventitious systems
Stems • Woody, herbaceous, vines • Support buds for leaves and flowers
Activity Time! Twig Handout
Leaves • Arrangement: • Opposite • Alternate • Simple vs. compound • Shape: • Needle • Entire • Lobed • Oval • Palmate
Parts of a Flower • Sepal • Petals • Stamen • Filament • Anther • Pollen • Pistil • Stigma • Style • Ovary • ovules
Seeds • Basic parts • Seed coat • Cotyledon • Embryo
Seed Dispersal • Methods • Hitchhikers • Winged • Within attractive fruits • Spring mechanisms • Shakers
Basic Physiology: Important processes • Photosynthesis • Respiration • Transpiration • Absorption • Translocation
Photosynthesis Conversion of energy from the sun to energy for life Carbon Dioxide + Water Sugar + Oxygen 6 CO2 + 6 H2O C6H12O6 + 6 O2
Pigment chromatography • Carotenes • Chlorophyll a • Chlorophyll b • Xanthophylls
Respiration Liberation of energy from the sun stored as sugars for use by the plant for plant functions. The reverse reaction of photosynthesis Sugar + Oxygen Carbon Dioxide + Water + Energy C6H12O6 + 6 O2 6 CO2 + 6 H2O + 673 kcal energy
Photosynthesis Respiration • produces food • stores energy • uses water • uses carbon dioxide • releases oxygen • occurs in sunlight • uses food • releases energy • produces water • produces carbon dioxide • uses oxygen • occurs in the dark as well as light Comparing photosynthesis and respiration
What did the stem say to the leaf after hearing the story of photosynthesis? What transpired next?
Plant Sweat = Transpiration • Process by which plants lose water from the leaf through the stomata
What Controls Transpiration? • Environmental factors such as soil water, humidity, temperature and air movement affect the loss of moisture from plants.
Absorption • Process by which water, minerals and nutrients are moved into the plant. • These materials move through the xylem elements (tubes). • Water movement is a passive process relying on internal water pressure (water potential). • Nutrient movement is an active process requiring energy.