thebacteriaofanodule根瘤中的细菌.ppt

(4) Chapter 37 Plant Nutrition 植物營養 Key Concepts Concept 37.1: Plants require certain chemical elements to complete their life cycle Concept 37.2: Soil quality is a major determinant of plant distribution and growth Concept 37.3: Nitrogen (N) is often the mineral that has the greatest effect on plant growth Concept 37.4: Plant nutritional adaptations (營養適應) often involve relationships with other organisms A Nutritional Network (營養網路) Every organism is an open system connected to its environment by a continuous exchange of energy and materials. In the energy flow and chemical cycling that keep an ecosystem alive, plants and other photosynthetic autotrophs perform the key step of transforming inorganic compounds into organic ones. Plants need sunlight as the energy source for photosynthesis. And to synthesize organic matter, plants also require raw materials in the form of inorganic substances: carbon dioxide (CO2), water (H2O), and a variety of minerals present as inorganic ions in the soil. With its ramifying root system and shoot system, a plant is extensively networked with its environment----the soil and air, which are the reservoirs of the plants inorganic nutrients. For a typical plant water and minerals come from the soil, while carbon dioxide (CO2) comes from the air. The branching root system and shoot system of a vascular plant Ensure extensive networking with both reservoirs of inorganic nutrients (無機營養) Concept 37.1: Plants require certain chemical elements to complete their life cycle Plants derive most of their organic mass from the CO2 of air, but they also depend on soil nutrients such as water and minerals Mineral nutrients Functions of water in plants Solvent in the cell Photosynthetic reactant Metabolic reactant or product Respiration Vacuolar content for cell elongation and extension Turgor pressure (膨壓) Others Macronutrients and Micronutrients巨量營養素與微量營養素 More than 50 chemical elements Have been identified among the inorganic substances in plant