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Botany for Gardeners

By Sharon Morrisey

Consumer Horticulture Agent

Milwaukee Co. UWEX

Botany is…

… the science of plants, including their structure

and function and the

environmental factors that affect their growth and

development.

Horticulture is…

…the science of producing, using and

maintaining ornamental plants,

fruits and vegetables.

It is garden (hortus) culture.

It is gardening!

Terminology & Classification

• Features

– Life cycle

– Misc. others

• Scientific names

– Binomial

– Latin

Life Cycles

• Annual

seed -----vegetative------flowering------seed

1 Year

• Biennial

vegetative flowering

Seed ---(rosette) (“bolt”)----seed

1st Year 2nd Year

• Perennial

seed ---vegetative & flowering & seed------

Many Years (some portion survives year to year)

Other Terminology • Stem types:

– herbaceous

– woody

• Leaf-holding ability:

– deciduous

– evergreen – needle; broadleaf

• Habit:

– tree

– shrub

– vine

– groundcover

– grass – turfgrass; ornamental grass

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Scientific Nomenclature Binomial nomenclature

• System to classify and name all living

things

• Developed by Carolus Linnaeus in 1750’s

• All plants known by two names

– Genus

– species

Quick Quiz:

What is this plant?

A. Trout lily

B. Dog tooth violet

C. Adder’s tongue

D. All of the above

Kingdoms

Animal Plant Fungi Bacteria Protista

Scientific names

• Genus

Picea

• Species

pungens

• Variety

var.

• Cultivar

‘Glauca’

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Genus species

Silver maple (Acer saccharinum)

Acer saccharum, A. platanunus, A. rubrum

“A single type of maple” Acer sp.

“Multiple types of maples” Acer spp.

Authorship

Parthenocissus quinquefolia (L.) Planchon

Varieties

Black Hills spruce, Picea glauca var. densata

Hybrids

Fragaria ×ananassa

(F. chiloensis and F. virginiana)

×Fatshedera lizei

(Fatsia japonica and Hedera helix)

Cultivars

Rubus idaeus ‘Autumn Britten’

Everbearing Raspberry

Hemerocallis ‘Eenie Weenie’

Daylily

Quick Quiz:

Which is correct:

A. Syringa Vulgaris

B. Syringa vulgaris

C. Syringa vulgaris

D. Syringa Vulgaris

Need lilac picture

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Trademarks & Other Names

Acer x freemanii ‘Jeffersed’ Red Sunset® Maple

Wave™ Petunia

Northpole™ Apple

Quick Quiz:

Which is it?

A. Variety

B. Hybrid

C. Cultivar

Dwarf Korean Lilac

Syringa meyeri 'Palibin'

Quick Quiz:

Which is it?

A. Variety

B. Hybrid

C. Cultivar

Arizona Red Shades

Gaillardia

Gaillardia x grandiflora

'Arizona Red Shades'

Quick Quiz:

Which is it?

A. Variety

B. Hybrid

C. Cultivar

Thornless Common

Honeylocust

Gleditsia triacanthos

var. inermis ‘Skyline’

Plant Anatomy, Physiology &

Environment

• Structure

– Roots

– Stems

– Leaves

– Flowers

– Fruits

– Seeds

• Function

– Photosynthesis

– Respiration

– Transpiration

– Translocation

– Hormones

• Environmental Factors – Light

– Temperature

– Soil

– Moisture

Principle Parts of a Vascular Plant

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Roots

• Functions:

– Anchor & support

– Absorb nutrients & water

– Store “food”

Roots • Function

– Storage

• Modified roots

– Tap roots

– Fiberous roots

– Sweet potatoes

– Aerial roots

» Banyon

trees

» Brace roots

on corn

Stems

• Function

– Supports leaves, buds, flowers, fruit and seeds

– Carries nutrients, water and food

• Vascular system

– Xylem

– Phloem

– Adds to girth and height

• Cambium (meristem)

Stem Anatomy

Stem Leaf Arrangement Stem Internal Structure

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Stem Growth Rings Stem Strength

Stems • Functions

– Storage

• Modifications – Above ground

» Crown

» Runner/ stolon

» Spur

– Below ground

» Rhizome

» Bulb

» Corm

» tuber

Stems Modifications: above ground

• runner/ stolon

• rhizome

Stems Modifications: above ground

Stems Modifications: below ground

• bulb

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Stems Modifications: below ground

• corm

Stems Modifications: below ground

• tuber

Buds

• Functions

– Produce stems, leaves, flowers (no

root buds)

– Site of growth meristems

Buds

Leaves • Functions

– Absorb sunlight

– Produce sugars through photosynthesis

– Transport

– Water regulation

– Temperature control

– Types

• Venation

• Shapes

Leaves

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Leaves

• Photosynthesis

light

Carbon dioxide + water------ sugar + oxygen

chlorophyll

• Respiration

dark

sugar/starch + oxygen ------ carbon dioxide + water + energy

Leaves • Cross-section

Leaves • Transpiration

Leaves • Translocation

– Water

– Sugars

– Nutrients

Leaves

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Leaf Types Leaf Venation

Leaf Shapes

Flowers

• Functions

– Produce viable seed(s) through

pollination

Flowers

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Flowers Flowers • Inflorescence

Fruits

• Functions

– Carry seeds

– Disperse seeds

– Is a mature ovary

Fruits

Fruits Seeds

• Functions

– Carry genetic information for next

generation

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Angiosperms Environmental Factors

Affecting Growth

• Light

• Temperature

• Water

• Soil

Light • Required for photosynthesis and

production of sugars

• Involved in transpiration

• Involved in all chemical

reactions

Light

• 3 components:

– Quantity

– Quality

– Duration

Light

• Quantity

– Light meters

• measure in footcandles (fc)

– Degree of contrast of shadow on white paper

Light

• Quantity

– Measured in footcandles (fc)

Outside full sun = 5,000 fc winter

10,000 fc summer

Indoor Houseplants:

lowest to survive = 50 fc

low light = 50 – 11 fc

medium = 100 – 250 fc

high = over 250 – 650 fc (Aspidistra elatior)

Cast Iron Plant

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Light

• Quantity

The light level outside in summer

in dense shade

is brighter than a south facing

window indoors in the winter.

Light

• Quality

– Spectrum of light

• Visible light

– ROY G. BIV

• Plants need most of red and blue

Light

• Quality

– Blue light responses

– Red and far-red responses

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Light

– Indoor Lighting

• Incandescent bulbs

– Mostly yellow to red and far red

– Produce heat

• Fluorescent bulbs

– Cool white – blues

– Warm white - reds

• “Grow Lights”

– Try to mimic spectrum of natural sunlight

» May have extra far red to promote flowering

Light

• Duration

– Photoperiod

• Length of day/ night

• Varies with the

season

• May be artificially

manipulated

Photoperiod

Photoperiod Light

• Plant reactions to photoperiod

– Long Day Plants (short night)

• Inhibits flowering

• Vegetative growth in summer; bloom in fall or spring

(Long day onions, form bulbs )

– Short Day Plants (long night)

• Promotes flowering (Chrysanthemums, pointsettias)

• Vegetative growth in spring; bloom in summer

– Day Neutral Plants

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Light

• Other Plant Reactions to Light

– Germination

• Some plants require light to germinate

– Excess light

• Burning

• Stunting

– Inadequate light

• Etiolation – Pale

– Stretched (“leggy’)

– Long internodes

Water

• Functions:

– Solvent for minerals & photosynthates

– Required for chemical reactions

– Germination

– Temperature control

– Turgor pressure

– Movement of minerals & photosynthates

• Diffusion

• Osmosis

• Transpiration

Water

• Factors affecting:

– Soil moisture

• On soil particles

• In pore spaces

• On organic matter

• Mulch to retain

• In containers

Water

• Factors affecting water use: – Light

– Air temperature

– Air humidity

– Wind

Transpiration increases when humidity is low, temperature is high and in windy conditions.

Water

• Methods of watering:

– Overhead

• sprinklers

– Directed

• Watering can

• Watering wand

• Soaker hoses

• Drip & trickle irrigation

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Water

• Timing:

– Early in the day

• Allows leaves to dry

• Droplets DO NOT act

like magnifiers and burn

leaves

– During flowering &

fruit production

Temperature

• Affects the rate of chemical reactions

– Q10 Effect • Reaction rate doubles with every increase of 10 degrees C.

– Photosynthesis (to 90 degrees)

– Respiration

• Only to a point

– Flowering • Respiration without photosynthesis leads to breakdown of

carbohydrates.

– Transpiration • Higher temps. Increase evaporation which “boils” water off

leaf surfaces which must be replaced by more pulled from soil

Temperature

• Transpiration

– Regulated by stomates

• Stomates close due to:

– Water stress (too little)

– High temperatures

– High CO2

– Darkness

Temperature

Other effects: • Heat cause bitterness in lettuce

• Heat causes “bolting” of cool season crops

• Cold treatment

– Required for dormany which is required for flowering of many plants including bulbs, fruit crops, etc.

– causes vernalization of “cole” crops (broccoli, cauliflower, cabbage, etc.)

• Heat and cold cause abortion of flowers and fruits

• Heat and cold may cause death of non-hardy plants

• Germination occurs at specific temperatures

• Cold soil reduces nutrient uptake

Plant Growth Regulators

– Hormones

• Auxin

• Gibberellins

• Cytokinin

• Abscisic acid

• ethylene

Plant Growth Regulators

– Auxin

• Promote cell elongation

• Inhibit lateral bud development (apical dominance)

• Promote lateral and adventitious roots

(rooting hormones)

• Involved in phototropism

• Promote flowering and fruit development

• High concentrations used as herbicides

(broadleaf weed killers)

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Plant Growth Regulators

– Gibberellins

• Promote stem elongation

• Promote germination

• Causes bolting in biennials

• May break bud and seed dormancy in plants usually

needing light or low temps. to break dormancy

• May induce flowering in long-day plants

• Gibberellins often work in concert with auxin

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Plant Growth Regulators

– Cytokinins

• Regulate cell division

• Are needed for germination

• Are found in meristems and immature fruits

• Migrate from roots to the shoot systems of plants

• Promote cytokinesis and cell differentiation

• May promote axilllary bud growth

• May retard leaf senescence

Plant Growth Regulators

– Abscisic Acid

• Growth-inhibiting hormone

• It goes into action during periods of stress

• Promotes dormancy activities such as formation of

bud scales and seed dormancy.

• Promotes stomata closure during leaf water deficit

conditions by activating K ions in the guard cells

• Plays role in senescence, the breakdown of cell

components before cell death.

Plant Growth Regulators

– Ethylene

• Inhibits cell elongation

• Promotes ripening in fruits

• Is the direct cause of leaf and fruit abscission

• Is produced by bruised tissues

• Is produced by some seeds when difficulties arise

during germination, which stimulates changes that

may help push the shoot t the soil surface.

• Promotes sprouting of many buds

• Can cause flowers to wilt

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Summary • Form and function are inter-related

– Form

• microscopic

• morphology

– Functions

• Photosynthesis & respiration

• Transpiration & translocation

• Plant hormones

• Effects of environmental factors

– Environmental conditions of the site

– Managed/ manipulated by the gardener