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Plant Form and Function Soil and Plant Nutrition. Plant biology, perhaps the oldest branch of science, is driven by a combination of curiosity and need curiosity about how plants work need to apply this knowledge judiciously to feed, clothe, and house a burgeoning human population.
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Plant Form and FunctionSoil and Plant Nutrition Plant biology, perhaps the oldest branch of science, is driven by a combination of curiosity and need curiosityabout how plants work needto apply this knowledge judiciously to feed, clothe, and house a burgeoning human population.
Plant Nutrition • What does a plant need to survive? • 9 macronutrients (required in large quantities) • C, H, N, O, P, S, K, Ca, Mg • 8 micronutrients (required in small quantities) • Fe, Cl, Cu, Mn, Zn, Mo, B, Ni • usually serve as cofactors of enzymatic reactions
Atmosphere N2 N2 Atmosphere Nitrate and nitrogenousorganiccompoundsexported inxylem toshoot system Soil Nitrogen-fixingbacteria N2 Denitrifyingbacteria H+ (From soil) NH4+ NH3 (ammonia) Soil NO3– (nitrate) NH4+ (ammonium) Nitrifyingbacteria Ammonifyingbacteria Organicmaterial (humus) Root Soil Bacteria and Nitrogen Availability Nitrogen-fixing bacteria convert atmospheric N2 plants absorb ammonium (NH4+), nitrate (NO3-)
Healthy Phosphate-deficient Potassium-deficient Nitrogen-deficient Mineral Deficiency • The most common deficiencies are those of nitrogen, potassium, and phosphorus
Hydroponics • Remove only one macronutrient to see effects on plant
Soil • Texture and Composition • Texture depends on size of particles • sand-silt-clay • loams: equal amounts of sand, silt, clay • Composition • Horizons-living organic matter • A horizon: topsoil, living organisms, humus • B horizon: less organic, less weathering than A horizon • C Horizon: “parent” material for upper layers • Soil conservation issues • fertilizers, irrigation, erosion
Soil Aeration • A mixture of mineral particles, decaying organic material, living organisms, air, and water, which together support the growth of plants
Nutritional Adaptations • Symbiotic Relationships • symbiotic nitrogen fixation • Legume root nodules contain bacteroids (Rhizobium bacteria) • mutualistic relationship • Crop rotation • Mycorrhizae • symbiotic associations of fungi and roots • mutualistic relationship • Ectomycorrhizae - mycelium forms mantle over root • Endomycorrhizae - does not form mantle; hyphae extend inward • Parasitic plants • plants that supplement their nutrition from host • mistletoe, dodder plant, Indian pipe • Carnivorous plants • supplement nutrition by digesting animals
EPIPHYTES Staghorn fern, an epiphyte PARASITIC PLANTS Host’s phloem Dodder Haustoria Dodder, a nonphotosynthetic parasite Mistletoe, a photosynthetic parasite Indian pipe, a nonphotosynthetic parasite CARNIVOROUS PLANTS Venus’ flytrap Sundews Pitcher plants Pitcher plant Venus flytrap
Phytoremediation • Poplars remove nitrates • Mustard removes uranium
WetlandsPhytoremediation Pesticide Levels (ppb) inGround Water Before & AfterPhytoremediation Activities