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Unformatted text preview: Lecture #17 Date ______ s Chapter 37 ~ Plant Nutrition Nutrients
s s s s Essential: required for the plant life cycle Macro- (large amounts) carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, potassium, calcium, magnesium Micro- (small amounts; cofactors of enzyme action) chlorine, iron, boron, manganese, zinc, copper, molybdenum, nickel Deficiency chlorosis (lack of magnesium; chlorophyll production) Soil
s s s s Determines plant growth & variety (also climate) Composition/horizons: topsoil (rock particles, living organisms, humuspartially decayed organic material) loams (equal amounts of sand, silt, and clay) Nitrogen Fixation
s s s s Atmosphere, 80% N2 Conversion to: ammonium (NH4+) or nitrate (NO3-) Bacteria types: Ammonifying (humus decomposition); nitrogen-fixing (atmospheric N2); nitrifying (convert NH4+ to NO3-); denitrifying (convert NO3- to N2) Nitrogen fixation; crop rotation Plant symbiosis, I
s s Rhizobium bacteria (found in root nodules in the legume family) Mutualistic: legume receives fixed N2; bacteria receives carbohydrates & organic materials Plant symbiosis, II
s s s Mycorrhizae (fungi); modified roots Mutualistic: fungus receives sugar; plant receives increased root surface area and increased phosphate uptake Two types: ectomycorrhizae ensheaths the root endomycorrhizae (90% of plants) through cell wall but not cell membrane Plant parasitism & predation
s s s Mistletoe (parasite) Epiphytes Carnivorous plants
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