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Plant Nutrition
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http://www.holmdel.k12.nj.us/faculty/cconover-pannone/Plants/Plant%20Nutrition.pdf
Nutritional Needs
 Autotrophic does not mean autonomous
 Plants need…
 Sun as an energy source
 Inorganic compounds as raw materials
 Water (H2O)
 CO2
 minerals
Essential Elements
 Macronutrients
(needed in relatively
large amounts)
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Carbon (C)
Oxygen (O)
Hydrogen (H)
Nitrogen (N)
Phosphorous (P)
Sulfur (S)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
 Micronutrients
(needed in very small
amounts)
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Chlorine
Iron
Manganese
Boron
Zinc
Copper
Nickel
Molybdenum
Nutrient Deficiency
 Lack of essential nutrients
 Exhibit specific symptoms
 Dependent on function of nutrient
 Dependent on solubility of nutrient
Water and mineral uptake
 Water uptake
 Cation uptake
 Plants cannot extract all
water from soil, only free
water
 Cation uptake is aided
by H+ secreation by
root cells (proton pump)
 osmosis
 Active transport
The Role of Soils
 Plants are dependent on soil quality
 Texture/structure
 Relative amounts of various sizes
of soil particles
 Composition
 Organic and inorganic
chemical component
 Fertility
Importance of organic matter
 Topsoil
 Most important to plant growth
 Rich in organic matter
 Humus
 Decomposing organic material
 Breakdown of dead organisms, feces, fallen leaves &
other organic refuse by bacteria and fungi
 Improves soil texture
 Reservoir of minerals
Importance of organic matter, cont.
 Topsoil, cont.
 Organisms
 1 teaspoon of topsoil has 5 billion
bacteria living with fungi, algae,
protists, insects, earthworms,
and nematodes
Soil health as a global issue
 Lack of soil
conservation
 Growing wheat
 Raising cattle
 Land exposed to wind
erosion
 Drought
 Soil conservation and
sustainable agriculture
 Maintaining healthy
environment
 Production of food
supply
 Economically viable
farming industry
Global Issues
 Fertility
 Erosion
 Irrigation
 Forestry destruction
Fertilizer
“Organic” fertilizers
 Manure, compost,
fishmeal
“Chemical”
fertilizers
 Commercially
manufactured
 N-P-K ratio
Irrigation
Most often the
limiting factor in
plant growth
Issues
 US rivers reduced
to trickles by
diversions of
water
 Soil becomes salty
and infertile
Erosion
 Topsoil - lost to
water and wind
erosion
 Precautions
 Trees as windbreaks
 Hillside crops
 Contour pattern
 Sustainable
Agriculture
Soil Reclamation
 Removal and storage of contaminated soils
 New method: phytoremediation
 Biological, nondestructive
 cheap
Nitrogen Fixation
N2
N2
Atmosphere
(gas)
(gas)
Soil
Nitrogen-Fixing
Bacteria
NH3
(ammonia)
H+ (from soil)
NH4+
(ammonium)
Denitrifying
bacteria
Nitrifying
bacteria
NO3(nitrate)
NH4+
Ammonifying
Bacteria
Organic material
(humus)
Root
Soybean Root Nodule
N fixation by Rhizobium bacteria
 Symbiotic relationship between nitrogen-fixing
bacteria and legumes
 Bacteroids inside nodules form
Mycorrhizae and Plant Nutrition
Symbiotic relationship
 Mycorrhizal fungus gets sugars from the plant
 In return, mycorrhizal fungus provides better
absorption of water and minerals for the
plant
 Ectomycorrhizae
versus
Endomycorrhizae
Unusual Adaptations
 Epiphytes
 Grows on branches and
trunks of trees
 Staghorn ferns, orchids
 Parasitic Plants
 Absorbs sugars and
minerals from living hosts
 Mistletoe, dodder, and Indian pipes
 Carnivorous Plants
 Photosynthetic, but obtain minerals and nutrients by killing
insects and other small animals
 Venus’ flytraps, pitcher plants, sundews