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Introduction to Horticulture and

Basic Botany Janie Becker, Extension Agent

UT/TSU Extension, Rutherford County

Horticulture vs. Botany

• Horticulture is the science, business and art of growing and promoting plants.

• Commercial plant production (banana peppers to bonsai)

• Landscape design

• Gardening of all sorts!

• Botany is the scientific study of plants.

• Structure/Function of Plants

• Environmental Factors Influence on Plants

• Physiology of Plants

• Plant Classification

What we will cover

• Plant Classification

• Plant Structure

• Plant Growth

• Plant Development

• Reproductive Development

• How Plants Function

Plant Classification

Defining characteristics of plants that aid in classification are as follows:

• Life Cycle

• Structure/Form

• Leaf Retention

• Climatic Adaptation

• Human Uses

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Life Cycle

Categories of Herbaceous Plants

-Annual

-Perennial

-Biennial

Related to Cold/Heat

Tolerance

-Cool Season Plants

-Warm Season Plants

Annuals

• Single season life cycle (in TN)

• Mature quickly, abundance of flowers

• Little effort to establish

• Bloom more, set seeds to perpetuate species

• Can be cool season/warm season plants

Warm Season Annuals

• Zinnias • Marigolds • Coleus • Geranium • Begonia • Lantana • Petunia

• Vinca • Cosmos • Calibrachoa • Impatiens • Cleome • Angelonia • Salvia

• Most vegetables grown here!

A Few Favorites

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Cool Season Annuals

• Pansy

• Viola

• Sweet Alyssum

• Delphinium

• Snap Dragon

• All plants in the Brassica family (kale, cabbage, mustard, broccoli, cauliflower, etc.)

Perennials

• Long lived, most come back each year

• Top will die back in winter for most herbaceous perennials

• Tender- Even crown may not survive harsh winters

• Typically, shorter bloom period than annuals

• Clump forming, spreading

• “1st year they sleep, 2nd they creep, 3rd they leap”

Many Choices!

• Salvia

• Coneflower

• Asters

• Hyssop

• Russian Sage

• Iris

• Penstemon

• Daylily

• Bleeding Heart

• Hellebore

• Heuchera

• Astilbe

• Hosta

• Lilies

• Bee balm

• Primrose

More Favorite Perennials

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Biennials

• Require two years to complete life cycle

• Grow vegetative structure in 1st year

• Overwinter with basal rosette of leaves present

• Flowers, fruit and seed develop in the second year

• Can bloom for two + years

Biennial Examples

• Onion

• Leek

• Foxglove

• Hollyhock

• Stock

• Carrot

• Parsley

• Queen Anne’s Lace

Structure & Form

• Size

• Growth Habit

• Form

• Texture

• Hardiness

Woody Plant Forms

• Vines

• Trees

• Shrubs

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Leaf Retention

• Deciduous Plants- Will drop leaves in the fall to prepare for dormancy

• “Evergreen” Plants- Retain leaves but continually shed old leaves to stimulate new leaf growth throughout the growing season.

• Broadleaf Evergreens (azalea, holly, magnolia)

• Needle-leaved Evergreens (pine, juniper, spruce)

Climatic Adaptation

• Cold Hardiness

• Plants are classified based on their tolerance of cold temps and the minimum temp they can withstand

• Tropical- 32˚F and above (frost sensitive)

• Subtropical- 32˚F or less for prolonged periods (frost hardy)

• Cool Season Fruit/Veggies/Flowers- daytime 55˚-75˚F

• Warm Season Fruit/Veggies/Flowers- daytime 70˚-95˚F

Rutherford County, 7A

Use Classifications

• Classifies plants by the most valued feature

• Ornamentals- Grown for aesthetic beauty or environmental enhancement

• Fruits/Nuts/Herbs/Vegetables- Grown for edibility

• A Fruit is any part of a plant that contains a seed

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Binomial Nomenclature, The Ultimate Classification for Plants!

• What it is: the system of giving a universal, 2-part name to each living organism, generally based in Latin or Greek etymology.

• Developed by Swedish physician, Carl Linnaeus (aka Carl von Linné)

• Groups plants together by functions and characteristics that they have together

Family Genus Species

(Lots) (Few) (One!)

Scientific Name

1st word=genus 2nd word=descriptive name (aka “specific epithet”)

Genus + specific epithet = SPECIES

Examples: Echinacea purpurea (purple coneflower)

Echinacea tennesseensis (Tennessee coneflower)

Plant Structure

Plant Structure

• Plant cells are independent units with a specialized purpose

• Plant parts can be grouped into two categories

1) Vegetative

2) Sexually reproductive

• Vegetative Parts- meristems, roots, stems, shoots, leaves, and buds.

• Sexual Parts- flowers, flower buds, seeds, fruits

Vegetative Plant Parts Meristems

• Growing Points

• Plant tissue in which cells divide, reproduce, and differentiate

• Healing Points “Plants Don’t Heal, They Seal!”

• Most common meristems are terminal (apical) and lateral.

• Apical (at an apex)- shoot tips, root tips, buds- responsible for increase in length of plant parts

• Lateral- stem and root diameter increases from lateral meristems called the cambium.

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Lateral Meristems=Sealing Points • Cut limbs showing lateral meristem activity

Cambium

Roots

• In addition to anchoring plants to the soil, roots function to absorb, conduct, and store nutrients.

• Primary Root- Originates from the lower end of the embryo of a seedling plant.

• Lateral or Secondary Roots- side branching of roots that develop off of other roots

• Root Hairs- formed from a single epidermal cell near the growing tip of a root. Absorb water and nutrients.

Root System Anatomy

Root Cap

-sloughed off cells

-protect meristematic tissue

Apical Meristem

-Origin of new root cells

Zone (Region) of Elongation

-cell size increases

-elongate and push into soil

Zone (Region) of Maturation -cells differentiate & become specific tissues

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Root Tissues/Cells

• Out of the maturation zone comes:

• Epidermis- outermost layer of cells responsible for water absorption. Includes single-celled root hairs.

• Cortex- cells are involved in the movement of water from the epidermis and in food storage

• Vascular Tissue- cells in the center of root and conduct water and food to other plant parts

Root Systems

• Fibrous System- primary root ceases to elongate and numerous lateral roots begin to develop-typically shallow

• Taproot System- primary root continues to develop with limited lateral root development- better anchored

Stems and Shoots

Function to support the plant and to store and conduct nutrients.

• Shoots- tissue of developing stems, leaves or flowers.

• Stem- holds the leaves up so they receive more light- can have single stem- trunk or multiple stems that form from the root crown.

• Nodes- points along a stem where shoots develop

• Internode- portion of stem located between nodes

• Lenticel A small opening on the surface of fruits, stems, and roots that allows exchange of gases between internal tissues and the atmosphere.

“Typical” Woody Stem

Year 3 Year 2 Year 1

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“Atypical” Stems

• Canes • A stem that lives only

a year or two

• Contain a large amount pith (soft tissue) in the center

• Mostly characterized as “brambles”, e.g, raspberries, blackberries, roses, etc.

• “Modified” Stems • Above-Ground

• Crowns (e.g., Peony)

• Stolons (e.g., Strawberry)

• Spurs (e.g., Pear)

• Below-Ground • Bulbs (e.g., Daffodil)

• Corms (e.g., Gladiolus)

• Rhizomes (e.g., Iris)

• Tubers (e.g., Potato)

Canes

Above Ground Modified Stems

Ex: Strawberry

Above Ground Modified Stems

Ex: Apple Spurs

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Below Ground Modified Stems

Ex: Potato Ex: Iris

Bulbs and Corms

Ex: Tulip Ex: Gladiolus

Vascular Tissue

• Cambium • Lateral meristematic tissue

in woody plants • Located between the

xylem and phloem and produces both tissues

Not all plants arrange their vascular tissues in the same way…

• Xylem • Transports water,

nutrients, & minerals from roots to upper portions of the plant

• Composed of dead, tubular cells called vessels

• Forms the “wood” of woody plants

• Phloem

• Conducts sugars from leaves to growing points, fruits, & storage areas

• Composed of long, living cells called sieve tubes.

• Comprises much of the inner bark of woody plants

Monocots vs. Dicots

• The two fundamental divisions within Angiosperms (Flowering Plants)

• Based on the number of cotyledons found in the embryo

• Cotyledons are the “seed leaves” packed within the seed and provide energy to the plant until the first “true leaves” are produced and photosynthesis begins

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Monocot seedling Dicot seedling A Comparison

Courtesy of V.H. Heywood

Vascular Comparison of Dicot/Monocot Stems

Leaves

• Two principle functions:

1) absorb sunlight for photosynthesis and

2) to transpire water into the atmosphere

Outer Leaf Parts

• Leaf Axil- junction of the petiole and the stem (eventual leaf scar-helpful in identification)

• Petiole- Attaches the leaf to the stem at the node, aka leaf “stem”

• Leaf Blade- Large surface area for energy absorption, transpiration, et al.

• Midrib/Veins- Conduct water, sugar and other compounds throughout the leaf

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Outer Leaf Anatomy Inner Anatomy of a

Leaf Blade • Epidermis- Protective layer on top and bottom of leaf, cell arrangement

determines leaf texture

• Cuticle- Part of epidermis that produces waxy layer called cutin. Protects leaf from dehydration and penetration of disease, increases with light intensity

• Mesophyll- middle layer, two layers- upper dense palisade and airy lower parenchyma which contain chloroplasts, the site of photosynthesis.

• Vascular Bundles- form at stem and extend through petiole into leaf blade, form venation pattern.

• Guard Cells- Epidermal cells on the underside of leaves that regulate the passage of water, oxygen and CO2. Protect stomata.

• Stomata- Openings on the underside of leaves through which gases are exchanged

Leaf Cross Section Leaf Terminology/Anatomy

• Structure of individual leaf

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Leaf Terminology/Anatomy

• Shape of leaf at tip or base • Shape of leaf perimeter –describes teeth, lobes, or lack thereof

Leaf Terminology/Anatomy

Leaf Terminology/Anatomy Buds

• Buds are meristematic structures along the stem that are composed of compressed immature shoots, leaves and/or flowers

• Weather sensitive, bud growth determines when plant will resume growth in spring and come out of dormancy

• Apical buds- tip of a stem or shoot

• Lateral Buds- on sides of stems, will form in axils, called axillary buds.

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Bud Growth & Arrangement

Leaf Arrangement

Year 3 Year 2 Year 1

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Questions before we

move on?

Sexual/Reproductive Structures

Flowers

Produce Seeds, Seeds, Seeds and more Seeds-

the goal of all flowers!!

• Angiosperms- covered seed- have true flowers, bloom, seed in fruit

• Gymnosperms- naked seed- no true flowers or fruit, but bear seeds uncovered or in cones (Conifers)

• Often showy for a reason to attract pollinators. If not showy, generally wind-pollinated.

• Less affected by environment than leaves. Again, good for ID and classification.

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Flower Parts

• Male Flower Parts

• Stamen (flowers often have a cluster of

stamens around the pistil)

• Anther (pollen sac)

• Filament (“stem”), supports the anther

• Female Flower Parts

• Pistil, aka Carpel (shaped like a bowling pin)

• Stigma (top)

• Style (middle)

• Ovary (bottom)

• Ovules – develop into seed(s) after pollination

Generalized Flower Structure

Flower Types & Descriptions

• Perfect – contains both pistils and stamens

• Imperfect – lacks a functioning pistil or stamen • Pistillate ♀- have pistils, no

stamens

• Staminate ♂- have stamens, no pistils

• Complete – contains

all 4 primary flower parts:

1)pistil2)stamen 3)petals 4)sepals

• Incomplete – lacks

one or more of the four primary parts and may be described as:

Plant types Based on Flowers

• Staminate plants ♂ male flowers only

• Pistillate plants ♀ female flowers only

• Most Holly are either male or female plants, must have both to produce berries

• Monoecious “one house” contains both male and female flowers on single plant

• Corn, Pecan, Rose

• Dioecious “two houses” contains only male or female flowers on a single plant

• Holly, Sumac, Juniper

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Floral Inflorescences

• Refers to how flowers are arranged on a floral stem

Pollination

• Transfer of pollen from an anther to a stigma by wind or by other pollinators- insects, animals, humans

• Cross pollination- combines different genetic material and produces stronger seed, plants are usually more successful, hybridization process.

• Self Pollination- plants have limited genetics, from same plant, usually less successful. Often manipulated by plant breeders.

How Flowering Plants Reproduce

Seeds

• Three Main Parts • Embryo – partially developed plant in a dormant state

• Radicle – embryonic root

• Hypocotyl – stem

• Cotyledons – seed leaves

• Plumule – underdeveloped stem and leaves

• Endosperm – food source (mother tissue)

• Seed Coat – protection from insects, diseases, and germination (mother tissue)

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Seeds Germination

• Moisture

• Oxygen

• Favorable temperature

• Light (sometimes)

• Storage • Seeds are living things! • They “live” longer when

maintained in a cool and dry environment.

• Keep seed packets air tight and store in a refrigerator or freezer

• Most seeds require time after maturity before they will germinate.

• Others will require:

• Cold Stratification

• Scarification

• Soaking

• Combinations of the above

Germination = resumption of seed growth; requires:

Seedling Development

Fruit

• Culinarily, something you eat for dessert

• Botanically, fruit is a ripened ovary

• Mature ovules (seeds)

• Ovary wall (flesh)

• Examples

• Tomatoes, cucumber, eggplant, beans

• Types of fruit

• Simple • Single flower with one pistil–

tomato, apple, okra

• Aggregate (compound) • Single flower with many

independent ovaries – strawberry, blackberry

• Multiple • Tight cluster of many flowers

– pineapple, mulberry, osage orange

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Fruit

• Fruit flesh and seed coat are both parent material with the same genes as the seed from which the plant grew

• Embryo (seed) is offspring material. Most traits will not be seen until it germinates and develops into plant.

Fruit

• Fruit flesh and seed coat are both parent material with the same genes as the seed from which the plant grew

• Embryo (seed) is offspring material. Most traits will not be seen until it germinates and develops into plant.

That’s interesting, but what does this mean to me?

Fruit Types Are Tied to Flower Type

One flower, One pistil

One flower, Many pistils,

Many flowers, Many pistils, Fused fruit

Plant Growth & Development

• Three major processes:

• Photosynthesis- the process by which green plants manufacture their own carbohydrates or nutrients to obtain a source of chemical energy. Occurs during daylight hours.

• Respiration- the process by which chemical energy is acquired by breaking down carbohydrates made during photosynthesis. Mostly occurs during the night.

• Transpiration- process by which a plant loses water vapor, primarily through leaf stomata. Continuous.

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Photosynthesis

• Photosynthesis – “to make with light”

• Requirements: • Light

• Carbon Dioxide

• Water

• Suitable Temperature

• Process – very

complicated, but a simple description

Photosynthesis in a nutshell

Respiration

• Respiration is the “opposite” of photosynthesis

• Carbohydrates are broken down and the energy released is used for life processes

• As night-time temperatures increase, respiration increases

Comparison

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Transpiration

• Transpiration is the process by which plants loose water vapor

• 90% of the water entering a plant is transpired

• Water movement is important in moving nutrients, minerals, sugars, and other compounds; as well as maintaining turgor pressure and evaporative cooling

Environmental Factors

• Primary environmental influencing plant growth

• Temperature

• Light

• Water

Temperature

• Temperature is the main environmental factor affecting plant growth • Germination

• Preferred Growing Season

• Hardiness

• Cold – Desiccation

• Heat – Wilt

• Growth and fruit set

• Temperature influences quality and susceptibility to pests and environmental stressors!

Light

Three principal characteristics:

1. Quantity • Intensity or brightness • Phototropism

2. Quality • Color or wavelengths • Red and blue light are most

important • Green is reflected by the

plant

3. Duration • Photoperiod – amount of

time a plant is exposed • Short-Day

• Flower during long nights • Mums and poinsettia

• Day-Neutral • Not influenced by day

length • Ever-bearing strawberries

• Long-Day • Flower during short nights • Most summer plants

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Water

• Water comprises all living things!

• The plant is no different! • Main component of

protoplasm – the living part of the cell

• Water Acquisition

• Root hairs • Vascular tissue • Stomates

• Quality • High/Low in salts • Temperature

• Quantity • Too much • Drowned Roots • Diseases

• Too little • Wilting

• Special structures • Leaves

Questions??

jbecker8@utk.edu

615-898-7710