Chapter 36: Plant Nutrition CHAPTER 36 Plant Nutrition

Chapter 36: Plant Nutrition The Acquisition of Nutrients The Acquisition of Nutrients Mineral Nutrients Essential to Plants Mineral Nutrients Essential to Plants Soils and Plants Soils and Plants

Chapter 36: Plant Nutrition Nitrogen Fixation Nitrogen Fixation Sulfur Metabolism Sulfur Metabolism Heterotrophic and Carnivorous Seed Plants Heterotrophic and Carnivorous Seed Plants

Chapter 36: Plant Nutrition The Acquisition of Nutrients Plants are photosynthetic autotrophs, producing all the compounds they need from carbon dioxide, water, and minerals.Plants are photosynthetic autotrophs, producing all the compounds they need from carbon dioxide, water, and minerals. They obtain energy from sunlight, carbon dioxide from the atmosphere, and nitrogen- containing ions and mineral nutrients from soil.They obtain energy from sunlight, carbon dioxide from the atmosphere, and nitrogen- containing ions and mineral nutrients from soil.4

Chapter 36: Plant Nutrition The Acquisition of Nutrients Plants explore their surroundings by growing rather than by locomotion.Plants explore their surroundings by growing rather than by locomotion.5

Chapter 36: Plant Nutrition Mineral Nutrients Essential to Plants Plants require fourteen essential mineral elements, all of which come from soil.Plants require fourteen essential mineral elements, all of which come from soil. Several essential elements fulfill multiple roles. Review Table 36.1Several essential elements fulfill multiple roles. Review Table

Chapter 36: Plant Nutrition Table 36.1 table jpg

Chapter 36: Plant Nutrition Mineral Nutrients Essential to Plants The six mineral nutrients required in substantial amounts are macronutrientsThe six mineral nutrients required in substantial amounts are macronutrients The eight required in much smaller amounts are micronutrients. Review Table 36.1The eight required in much smaller amounts are micronutrients. Review Table

Chapter 36: Plant Nutrition Mineral Nutrients Essential to Plants Deficiency symptoms suggest what essential element a plant lacks. Review Table 36.2Deficiency symptoms suggest what essential element a plant lacks. Review Table

Chapter 36: Plant Nutrition Table 36.2 table jpg

Chapter 36: Plant Nutrition Mineral Nutrients Essential to Plants Biologists discovered the essentiality of each mineral nutrient by growing plants on nutrient solutions lacking the test element. Review Figure 36.2Biologists discovered the essentiality of each mineral nutrient by growing plants on nutrient solutions lacking the test element. Review Figure

Chapter 36: Plant Nutrition Figure 36.2 figure jpg

Chapter 36: Plant Nutrition Soils and Plants Soils have complex structure, with living and nonliving components.Soils have complex structure, with living and nonliving components. They contain water, gases, and inorganic and organic substances.They contain water, gases, and inorganic and organic substances. They typically consist of two or three horizontal zones called horizons. Review Figures 36.3 and Table 36.3They typically consist of two or three horizontal zones called horizons. Review Figures 36.3 and Table

Chapter 36: Plant Nutrition Figure 36.3 figure jpg

Chapter 36: Plant Nutrition Table 36.3 table jpg

Chapter 36: Plant Nutrition Soils and Plants Soils form by mechanical and chemical weathering of rock.Soils form by mechanical and chemical weathering of rock.16

Chapter 36: Plant Nutrition Soils and Plants Plants obtain some mineral nutrients by ion exchange between the soil solution and the surface of clay particles. Review Figure 36.5Plants obtain some mineral nutrients by ion exchange between the soil solution and the surface of clay particles. Review Figure

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Chapter 36: Plant Nutrition Soils and Plants Farmers use fertilizer to make up for deficiencies in soil mineral nutrient content, and apply lime to raise low soil pH.Farmers use fertilizer to make up for deficiencies in soil mineral nutrient content, and apply lime to raise low soil pH.19

Chapter 36: Plant Nutrition Soils and Plants Plants affect soils in various ways, helping them form, adding material such as humus, and removing nutrients.Plants affect soils in various ways, helping them form, adding material such as humus, and removing nutrients.20

Chapter 36: Plant Nutrition Nitrogen Fixation A few soil bacteria species are responsible for almost all nitrogen fixation.A few soil bacteria species are responsible for almost all nitrogen fixation. Some live free in the soil; others live symbiotically as bacteroids within plant roots.Some live free in the soil; others live symbiotically as bacteroids within plant roots.21

Chapter 36: Plant Nutrition Nitrogen Fixation In nitrogen fixation, nitrogen gas (N 2 ) is reduced to ammonia (NH 3 ) or ammonium ions (NH 4 + ) in a reaction catalyzed by nitrogenase. Review Figure 36.7In nitrogen fixation, nitrogen gas (N 2 ) is reduced to ammonia (NH 3 ) or ammonium ions (NH 4 + ) in a reaction catalyzed by nitrogenase. Review Figure

Chapter 36: Plant Nutrition Figure 36.7 – Part 1 figure 36-07a.jpg

Chapter 36: Plant Nutrition Figure 36.7 – Part 2 figure 36-07b.jpg

Chapter 36: Plant Nutrition Nitrogen Fixation Nitrogenase requires anaerobic conditions, but bacteroids in root nodules require oxygen for respiration.Nitrogenase requires anaerobic conditions, but bacteroids in root nodules require oxygen for respiration. Leghemoglobin helps maintain the oxygen supply to bacteroids.Leghemoglobin helps maintain the oxygen supply to bacteroids.25

Chapter 36: Plant Nutrition Nitrogen Fixation Nodule formation requires an interaction between the root system of a legume and Rhizobium bacteria. Review Figure 36.8Nodule formation requires an interaction between the root system of a legume and Rhizobium bacteria. Review Figure

Chapter 36: Plant Nutrition Figure 36.8 – Part 1 figure 36-08a.jpg

Chapter 36: Plant Nutrition Figure 36.8 – Part 2 figure 36-08b.jpg

Chapter 36: Plant Nutrition Nitrogen Fixation Nitrogen-fixing bacteria reduce atmospheric N 2 to ammonia, but most plants take up both ammonium and nitrate ions.Nitrogen-fixing bacteria reduce atmospheric N 2 to ammonia, but most plants take up both ammonium and nitrate ions. Nitrifying bacteria oxidize ammonia to nitrate.Nitrifying bacteria oxidize ammonia to nitrate. Plants take up nitrate and reduce it back to ammonia, something animals are incapable of doing. Review Figure 36.9Plants take up nitrate and reduce it back to ammonia, something animals are incapable of doing. Review Figure

Chapter 36: Plant Nutrition Nitrogen Fixation Denitrifying bacteria return N 2 to the atmosphere, completing the biological nitrogen cycle. Review Figure 36.9Denitrifying bacteria return N 2 to the atmosphere, completing the biological nitrogen cycle. Review Figure

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Chapter 36: Plant Nutrition Sulfur Metabolism Plants take up sulfate ions and reduce them, forming cysteine and methionine.Plants take up sulfate ions and reduce them, forming cysteine and methionine. Cysteine is the major precursor for other sulfur-containing compounds in plants and in animals, which must obtain organic sulfur from plants.Cysteine is the major precursor for other sulfur-containing compounds in plants and in animals, which must obtain organic sulfur from plants.32

Chapter 36: Plant Nutrition Heterotrophic and Carnivorous Seed Plants A few heterotrophic plants are parasitic on other plants.A few heterotrophic plants are parasitic on other plants.33

Chapter 36: Plant Nutrition Heterotrophic and Carnivorous Seed Plants Carnivorous plants are autotrophs that supplement their nitrogen supply by feeding on insects.Carnivorous plants are autotrophs that supplement their nitrogen supply by feeding on insects.34