Download Basic Botany

Botany is…
Basic Botany
Master Gardener General Training
… the science of plants, including
their structure and function and the
environmental factors that affect
their growth and development.
By Sharon Morrisey
Consumer Horticulture Agent
Milwaukee Co. UWEX
Horticulture is…
MG General Training
• Botany
…the science of producing, using
and maintaining ornamental plants,
fruits and vegetables.
It is garden (hortus) culture.
– Anatomy
– Physiology
– Factors affecting plant growth
• Horticulture
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Fruits (pomology & viticulture)
Vegetables (olericulture)
Trees, shrubs and vines (woodies)
Flowers (floriculture)
Lawns
Houseplants
• Entomology (insects)
• Plant Pathology (diseases)
• Soil Science
Life Cycles
Terminology & Classification
• Annual
• Features
– Life cycle
– Misc. others
• Scientific names
– Binomial
– Latin
seed -----vegetative------flowering------seed
1 Year
• Biennial
vegetative
flowering
Seed ---(rosette) (“bolt”)----seed
2nd Year
1st Year
• Perennial
seed ---vegetative & flowering & seed-----Many Years
(some portion survives year to year)
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Other Terminology
Nomenclature
• Stem types:
– herbaceous
– Woody
• Leaf-holding ability:
– Deciduous
– Evergreen – needle; broadleaf
• Habit:
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Tree
Shrub
Vine
Groundcover
grass
Binomial nomenclature
• System to classify and name all living
things
• Developed by Carolus Linneaus in 1750’s
• All plants known by two names
– Genus
– species
Classification
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Scientific names
• Genus
Picea
• Species
pungens
• Variety
var.
• Cultivar
Pneumonic device to remember: King David Came Over From Greece Sunday!
Identification Keys
‘Glauca’
Plant Anatomy &
Physiology
• Structure
• Function
• Terminology
Principle Parts of a Vascular Plant
Plant Parts
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Roots
Stems
Buds
Leaves
Flowers
Fruits
Seeds
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Roots
Roots
• Functions:
– Anchor & support
– Absorb nutrients & water
– Store “food”
Root Meristem
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)
Stems
Stems
– Storage
• Modifications
– Above ground
» Crown
» Runner/ stolon
» Spur
– Below ground
» Rhizome
» Bulb
» Corm
» tuber
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Stems
Stems
Stems
Stems
Stems
Stems
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Stems
Modifications: above ground
• runner/ stolon
Stems
Modifications: below ground
• rhizome
Stems
Modifications: below ground
• bulb
Stems
Modifications: below ground
• corm
Stems
Buds
Modifications: below ground
• tuber
• Functions
– Produce stems, leaves, flowers (no
root buds)
– Site of growth meristems
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Leaves
Buds
• Functions
– Absorb sunlight
– Produce sugars through photosynthesis
– Transport
– Water regulation
– Temperature control
– Types
• Venation
• Shapes
Leaves
Leaves
• Photosynthesis
light
Carbon dioxide + water------ sugar + oxygen
chlorophyll
• Respiration
dark
sugar/starch + oxygen ------ carbon dioxide + water + energy
Leaves
Leaves
• Cross-section
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Leaves
• Transpiration
Leaves
• Stomates with guard cells
Roots
• Transpiration
Leaves
• Translocation
– Water
– Sugars
– nutrients
Leaves
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Leaves
Leaves
Leaves
Leaves
Leaves
Flowers
• Functions
– Produce viable seed(s) through
pollination
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Flowers
Flowers
Flowers
Asteraceae
Flowers
Fruits
• Inflorescence
• Functions
– Carry seeds
– Disperse seeds
– Is a mature ovary
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Fruits
Fruits
Seeds
Seeds
• Dicot
– Two seed leaves
• Functions
– Carry genetic information for next
generation
Seeds
Factors Affecting Growth
• Monocot
– One seed leaf
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Light
Water
Temperature
Carbon/Nitrogen Ratio
Plant Growth Regulators
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Light
• Required for photosynthesis and production
of sugars
Light
• 3 components:
– Quantity
• Involved in transpiration
– Quality
• Involved in all chemical reactions
– Duration
Light
• Quantity
Light
• Quantity
– Measured in footcandles (fc)
– Light meters
• measure in footcandles (fc)
– Degree of contrast of shadow on white paper
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
Light
• Quantity
Light
• Quality
– Spectrum of light
The light level outside in summer
in dense shade
is brighter than a south facing window
indoors in the winter.
• Visible light
– ROY G. BIV
• Plants need most of red and blue
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Light
• Quality
– Blue light responses
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Photosynthesis
Petiole length
Internode length
Leaf expansion
Phototropic reactions
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Light
• Quality
– Red & Far Red responses
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Photosynthesis
Seed germination, seedling growth
Fruit ripening
Tuber and bulb formation
Photoperiodism
flowering
Light
– Indoor Lighting
• Incandescent bulbs
– Mostly yellow to red and far red
– Produce heat
• Fluorescent bulbs
– Cool white – blues
– Warm white - reds
Light
• Duration
– Photoperiod
• Length of day/ night
• Varies with the season
• May be artificially manipulated
• “Grow Lights”
– Try to mimic spectrum of natural sunlight
» May have extra far red to promote flowering
Photoperiod
Photoperiod
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Light
• Longest day/ shortest night
– Summer Solstice, June 21st
– Midsummer’s day
• Shortest day / Longest night
– Winter Solstice December 21
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 )
• Half way between
– Vernal equinox, March 20
– Autumnal equinox, September 20
• Ground Hog’s Day
– February 2
– Exactly halfway between Winter Solstice and Vernal
Equinox
– Short Day Plants (long night)
• Promotes flowering (Chrysanthemums, pointsettias)
• Vegetative growth in spring; bloom in summer
– Day Neutral Plants
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:
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Solvent for minerals & photosynthates
Required for chemical reactions
Germination
Temperature control
Turgor pressure
Movement of minerals & photosynthates
Water
• Factors affecting:
– Soil moisture
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On soil particles
In pore spaces
On organic matter
Mulch to retain
In containers
• Diffusion
• Osmosis
• Transpiration
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Water
• Factors affecting:
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Light
Air temperature
Air humidity
Wind
Transpiration increases when humidity is low,
temperature is high and on windy conditions.
Water
• Methods of watering:
– Overhead
• sprinklers
– Directed
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Watering can
Watering wand
Soaker hoses
Drip & trickle irrigation
Water
Temperature
• Affects the rate of chemical reactions
• Timing:
– Early in the day
• Allows leaves to dry
• Droplets DO NOT act like magnifiers and burn
leaves
– During flowering & fruit production
– 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
• 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.)
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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
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Carbon/ Nitrogen Ratio
– Sources of Carbon:
• Photosynthates – sugars & starches
• Wood, dry leaves, dry plant parts
– Sources of Nitrogen:
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Absorbed from soil
Lightning
Green leaves, stems and plant parts
Fertilizer
Manure
Carbon/ Nitrogen Ratio
– Low C/N ratio
• More N than C (high N fertilizer)
• Little C being produced (low photosynthesis)
• C being broken down (high respiration)
– High C/ N ratio
Carbon/ Nitrogen Ratio
– Carbon & photosynthesis
• Increased photosynthesis creates more
carbohydrates
– Carbon & respiration
• Increased respiration breaks down carbohydrate
• Releases energy
Plant Growth Regulators
– Hormones
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Auxin
Gibberellins
Cytokinin
Abscisic acid
ethylene
• Increases flowering and fruiting
• Mulches – high carbon
– Require extra nitrogen
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
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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
Plant Growth Regulators
– Cytokinins
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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
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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
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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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