Plant Physiology

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Plant Physiology
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Photosynthesis

• requires light
• requires chlorophyll
• requires CO2
• needs water
• produces sugars
  
  (energy)
• oxygen is released

6CO2 6H2O C6H1206 O6
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Respiration
Unlike photosynthesis, respiration takes place at
all times, day and night
C6H1206 O2 CO2 H2O Heat
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Leaf Cross-section
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• Photosynthesis
• Produces food
• Releases oxygen
• Occurs in all cells containing chlorophyll
• Uses water
• Uses carbon dioxide
• Occurs in light

• Respiration
• Uses food for plant energy
• Releases energy
• Occurs in all cells
• Uses oxygen
• Produces water
• Produces carbon dioxide
• Occurs in light as well as dark

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Transpiration
The process by which plants lose water, primarily
through stomata.
The amount of water loss from a plant through
transpiration depends on environmental factors
such as temperature, humidity and air movement.
Transpiration is also important in cooling plant
parts through evaporation.
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Stomata
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Water Movement
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Guttation
Occurs mainly at night due to root pressure.
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Light
Quantity - maximum during the summer and minimum
during the winter and can be controlled by shade
cloth.
Quality - refers to the color or wavelength that
reaches the plant.
Duration - refers to the amount of time a plant
is exposed to light.
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Temperature
Temperature is a factor in flower and fruit
production such as chilling indexes needed for
peach production.
Plants will produce maximum growth when day
temperatures are 10 to 15 degrees higher than
night.
Plants can be classified as either hardy or
nonhardy depending on their ability to withstand
cold temperatures.
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Plant Nutrition

• 16 Essential Elements
• Necessary for a plant to complete its life cycle
• Must play a specific role in the plants life
• No other element can substitute for it

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Plant Nutrition
Primary
C H O
N P K
Ca Mg S
Micronutrients
Secondary
B Cu Cl Mn Zn Fe Mo
C HOPKNS CaFe Mg B Mn CuZn MoCl
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C - CarbonH - HydrogenO - Oxygen P -
PhosphorousK - PotassiumN - Nitrogen Ca -
CalciumMg - MagnesiumS - Sulfur B - BoronCu -
CopperCl - ChlorineMn - ManganeseZn - ZincFe
- IronMo - Molybdenum
Derived from the atmosphere and are the main
building blocks of the plant.

Derived mainly through fertili-zation and mineral
release from soil degradation. Plant growth.

Primary Nutrients

Derived mainly through fertilization, liming and
mineral release from soil degradation. Important
in enzymes and protein formation.
Secondary Nutrients
Derived mainly from natural occurrence, weathered
rock and through fertilization. Needed in less
quantity than other elements and are important in
various enzyme activities.

Micronutrient Nutrients
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Nutrient Absorption
Active process - Oxygen must be present

• Mass Flow

• Root Intercept

• Diffusion

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Factors Inhibiting Nutrient Uptake
Soil Aeration
Nutrient Availability
Soil Temperature
Type of Plant
Soil Moisture
Effects of Other Nutrient
Soil pH
Solubility of Nutrient