Transcript Root
Chapter 37: Plant Nutrition 1. What are the nutritional requirements of plants? Figure 37.2 The uptake of nutrients by a plant: a review CO2, the source of carbon for Photosynthesis, diffuses into leaves from the air through stomata. H2O CO2 O2 Through stomata, leaves expel H2O and O2. O2 Minerals Roots absorb H2O and minerals from the soil. CO2 H2O Roots take in O2 and expel CO2. The plant uses O2 for cellular respiration but is a net O2 producer. Chapter 37: Plant Nutrition 1. What are the nutritional requirements of plants? 2. Why do plants need K+? Mg++ P S N - Macronutrients – needed in large amounts (9) - Micronutrients – needed in small amounts (8) Table 37.1 Essential Elements in Plants Chapter 37: Plant Nutrition 1. What are the nutritional requirements of plants? 2. Why do plants need K+? Mg++ P S N 3. What makes up soil? - Weathered rock - Topsoil – mixture of weathered rock, living organisms, & humus - Humus – remains of partially decayed organic matter - Loams – most fertile soils made of equal amounts of clay, silt & sand Figure 37.5 Soil horizons The A horizon is the topsoil, a mixture of broken-down rock of various textures, living organisms, and decaying organic matter. A B The B horizon contains much less organic matter than the A horizon and is less weathered. C The C horizon, composed mainly of partially broken-down rock, serves as the “parent” material for the upper layers of soil. Chapter 37: Plant Nutrition 1. 2. 3. 4. What are the nutritional requirements of plants? Why do plants need K+? Mg++ P S N What makes up soil? How do minerals become available to plant roots? - Cation exchange Figure 37.6 The availability of soil water and minerals Soil particle surrounded by film of water Root hair K+ – Water available to plant Soil particle – Cu2+ – – – K+ – – Mg2+ – + – K Ca2+ H+ H2O + CO2 H2CO3 HCO3– + H+ Root hair Air space (a) Soil water. A plant cannot extract all the water in the soil because some of it is tightly held by hydrophilic soil particles. Water bound less tightly to soil particles can be absorbed by the root. (b) Cation exchange in soil. Hydrogen ions (H+) help make nutrients available by displacing positively charged minerals (cations such as Ca2+) that were bound tightly to the surface of negatively charged soil particles. Plants contribute H+ by secreting it from root hairs and also by cellular respiration, which releases CO2 into the soil solution, where it reacts with H2O to form carbonic acid (H2CO3). Dissociation of this acid adds H+ to the soil solution. Chapter 37: Plant Nutrition 1. 2. 3. 4. 5. What are the nutritional requirements of plants? Why do plants need K+? Mg++ P S N What makes up soil? How do minerals become available to plant roots? How is soil conservation achieved? - Fertilizers - N-P-K - Organic - Irrigation - problems - Erosion prevention Chapter 37: Plant Nutrition 1. 2. 3. 4. 5. 6. What are the nutritional requirements of plants? Why do plants need K+? Mg++ P S N What makes up soil? How do minerals become available to plant roots? How is soil conservation achieved? How do plants obtain nitrogen? - nitrogen-fixing bacteria Figure 37.9 The role of soil bacteria in the nitrogen nutrition of plants Atmosphere N2 Atmosphere Soil N2 Nitrogen-fixing bacteria H+ (from soil) Soil NH3 (ammonia) NH4 + (ammonium) Ammonifying bacteria Organic material (humus) Figure 37.9 The role of soil bacteria in the nitrogen nutrition of plants Atmosphere N2 N2 Atmosphere Soil N2 Nitrogen-fixing bacteria Denitrifying bacteria H+ (from soil) Soil NH3 (ammonia) NH4 + (ammonium) Ammonifying bacteria Organic material (humus) Nitrifying bacteria NO3 – (nitrate) Figure 37.9 The role of soil bacteria in the nitrogen nutrition of plants Atmosphere N2 N2 Atmosphere Soil N2 Nitrogen-fixing bacteria Denitrifying bacteria H+ (from soil) Soil Nitrate and nitrogenous organic compounds exported in xylem to shoot system NH4 + NH3 (ammonia) NH4 + (ammonium) Nitrifying bacteria NO3 – (nitrate) Ammonifying bacteria Organic material (humus) Assimilation Legumes have root nodules with symbiotic bacteria Rhizobium Root Figure 37.10 Root nodules on legumes 5 m Bacteroids within vesicle Nodules Roots (a) Pea plant root. The bumps on this pea plant root are nodules containing Rhizobium bacteria. The bacteria fix nitrogen and obtain photosynthetic products supplied by the plant. (b) Bacteroids in a soybean root nodule. In this TEM, a cell from a root nodule of soybean is filled with bacteroids in vesicles. The cells on the left are uninfected. Chapter 37: Plant Nutrition 1. 2. 3. 4. 5. 6. 7. What are the nutritional requirements of plants? Why do plants need K+? Mg++ P S N What makes up soil? How do minerals become available to plant roots? How is soil conservation achieved? How do plants obtain nitrogen? What are some nutritional adaptations that aid plants? Figure 37.13 Unusual Nutritional Adaptations in Plants EPIPHYTES Staghorn fern, an epiphyte PARASITIC PLANTS Host’s phloem Dodder Haustoria Mistletoe, a photosynthetic parasite Dodder, a nonphotosynthetic parasite Indian pipe, a nonphotosynthetic parasite CARNIVOROUS PLANTS Venus’ flytrap Pitcher plants Sundews 37.13 Sun Dew Trap Prey • Please take Ch. 38 Notes & Ch. 39 Notes from the table. • Animal Test grades for all class periods are now final in PowerSchool. • If you want me to check your PPT project & provide feedback, I must receive it in my inbox by MIDNIGHT tonight. Any project received after that time will be counted as your final submission.