Plant Nutrition

1
Plant Nutrition

• Powerpoint adopted from http//209.85.173.132/sea
  rch?qcacheMhSZ0kbKXowJteachers.sduhsd.net/lolso
  n/AP2520Biology/Powerpoint2520files/35Ch37PlantN
  utrition2005a.pdfapbiologyplantnutritionhlen
  ctclnkcd2gluslrlang_enclientsafari
• http//www.holmdel.k12.nj.us/faculty/cconover-pann
  one/Plants/Plant20Nutrition.pdf

2
Nutritional Needs

• Autotrophic does not mean autonomous
• Plants need
• Sun as an energy source
• Inorganic compounds as raw materials
• Water (H2O)
• CO2
• minerals

3
Essential Elements

• Macronutrients (needed in relatively large
  amounts)
• Carbon (C)
• Oxygen (O)
• Hydrogen (H)
• Nitrogen (N)
• Phosphorous (P)
• Sulfur (S)
• Potassium (K)
• Calcium (Ca)
• Magnesium (Mg)

• Micronutrients (needed in very small amounts)
• Chlorine
• Iron
• Manganese
• Boron
• Zinc
• Copper
• Nickel
• Molybdenum

4
Nutrient Deficiency

• Lack of essential nutrients
• Exhibit specific symptoms
• Dependent on function of nutrient
• Dependent on solubility of nutrient

5
Water and mineral uptake

• Water uptake
• Plants cannot extract all water from soil, only
  free water
• osmosis

• Cation uptake
• Cation uptake is aided by H secreation by root
  cells (proton pump)
• Active transport

6
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

7
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

8
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

9
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

10
Global Issues

• Fertility
• Erosion
• Irrigation
• Forestry destruction

11
Fertilizer

• Organic fertilizers
• Manure, compost, fishmeal
• Chemical fertilizers
• Commercially manufactured
• N-P-K ratio

12
Irrigation

• Most often the limiting factor in plant growth
• Issues
• US rivers reduced to trickles by diversions of
  water
• Soil becomes salty and infertile

13
Erosion

• Topsoil - lost to water and wind erosion
• Precautions
• Trees as windbreaks
• Hillside crops
• Contour pattern
• Sustainable Agriculture

14
Soil Reclamation

• Removal and storage of contaminated soils
• New method phytoremediation
• Biological, nondestructive
• cheap

15
Nitrogen Fixation
N2 (gas)
N2 (gas)
Atmosphere
Soil
Denitrifying bacteria
Nitrogen-Fixing Bacteria
H (from soil)
NH4 (ammonium)
Nitrifying bacteria
NH3 (ammonia)
NO3- (nitrate)
NH4
Ammonifying Bacteria
Root
Organic material (humus)
16
Soybean Root Nodule

• N fixation by Rhizobium bacteria
• Symbiotic relationship between nitrogen-fixing
  bacteria and legumes
• Bacteroids inside nodules form

17
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

18
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

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• Carnivorous Plants
• Photosynthetic, but obtain minerals and nutrients
  by killing insects and other small animals
• Venus flytraps, pitcher plants, sundews