Plant Nutrition

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Plant Nutrition

• Chapter 37

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• Uptake of nutrients happens in roots and leaves.
• Roots, through mycorrhizae and root hairs, absorb
  water and minerals from soil.
• Essential nutrient required for plant to grow
  from seed and complete life cycle.
• Macronutrients needed in large numbers
  micronutrients are not.

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• Texture, pH, composition of soil determines types
  of plants that grow in area.
• Soil may be acidic or basic because of minerals
  that absorb in soil.

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• Soil made of topsoil - mixture of rock, living
  organisms, and humus (residue of partially
  decayed organic material)
• Can be washed away by water, robbing soil of
  important nutrients.

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• Plants cannot use nitrogen in form of N2.
• Bacteria, nitrogen-fixing bacteria, convert N2 to
  NH3 (ammonia), via nitrogen fixation.

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• Roots also form symbioses with organisms
  relationships that are helpful to both species.
• Legumes roots have swellings called nodules -
  plant cells that contain nitrogen-fixing
  bacteria.

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• Crop rotation increases amount of nitrogen in
  soil.
• Farmers do this so nitrogen-rich plants (legumes)
  can add nitrogen to different soil areas.

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• Mycorrhizae - modified roots, made of symbiotic
  relationships between fungi and roots.
• Fungus increases surface area for water uptake,
  secretes growth factors that stimulate roots to
  grow and branch, and produces antibiotics.
• Mycorrhizae - hyphae - help increase surface
  area also invade cells by digesting cell wall.

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http//www.plantpath.wisc.edu/tddl/tddl/disimg/bp/
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• Some plants - parasites - will not
  photosynthesize.
• Tap into other plants that do.
• Epiphytes (orchids) - not parasitic grow on
  other plants.
• Some plants evolved modified leaves that trap
  insects.

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