Nutrient Acquisition by Plants An Ecological Perspective

1: Soil Factors Affecting Nutrient Bioavailability. Introduction. Release of Nutrients from the Soil Solid Phase. Nutrient Movement Through the Soil Solution. Nutrient Uptake by the Root System. Modeling Nutrient Bioavailability. Summary. References. 2: Decomposition and Mineralization of Nutrients from Litter and Humus. Introduction. Decomposition. Early (Litter) Decomposition. Moisture. Temperature. Litter Quality. Nitrogen Availability. Completeness of Decomposition. Late-Stage Decomposition. (Humus and Soil Organic Matter). Moisture. Temperature. Humus Quality. Nitrogen Availability. 1: Soil Factors Affecting Nutrient Bioavailability. Introduction. Release of Nutrients from the Soil Solid Phase. Nutrient Movement Through the Soil Solution. Nutrient Uptake by the Root System. Modeling Nutrient Bioavailability. Summary. References. 2: Decomposition and Mineralization of Nutrients from Litter and Humus. Introduction. Decomposition. Early (Litter) Decomposition. Moisture. Temperature. Litter Quality. Nitrogen Availability. Completeness of Decomposition. Late-Stage Decomposition. (Humus and Soil Organic Matter). Moisture. Temperature. Humus Quality. Nitrogen Availability. Applying the Model: Differences. from Simple Functional Balance. Additional Questions: Stress, Root Turnover, Low Set Points of Woody Plants. Role of Root Lifetime. Effects of Water Stress and Salinity. Why Is Uptake so Low in Some Species? Conclusions. Summary. Appendix: Definitions of Terms and Symbols. References. 5: Biological Nitrogen Fixation Associated with Angiosperms in Terrestrial Ecosystems. Introduction. Cyanobacteria and Their Symbioses. Free-Living Nitrogen-Fixing Cyanobacteria. Cyanobacterial Symbioses. Cycads. Gunnera. Non-nodulating Associations Between Angiosperms and Non-photosynthetic Nitrogen-Fixing Microorganisms. Loose Associations. Endophytic Associations. Kallar Grass. Rice. Sugarcane. Nodulated Plants: Symbioses with Prankia and Rhizobia. Actinorhizal Plants. Parasponia. Legumes. Ecological Role and Uses of Nodulated Plants. Actinorhizal Plants. Legumes. Nodulated and Non-nodulated Plants. Geographical Trends. Dry, Flooded and Saline Environments. Possible Chemical Constraints. Rhizobial Constraints. Problems with Nodulated LegumesMycorrhizas, Cluster (Proteoid) Roots and Other Nutrient Acquisition Systems. How Much Nitrogen Is Fixed Biologically? What Does the Future Hold for Nitrogen-Fixing Plants? Summary. References. 6: Homeostatic Processes for the Optimization of Nutrient Absorption: Physiology and Molecular Biology. Introduction. Kinetic Constants for Ion Influx. Definitions. Methodology. Effects of Nutrient Status on Kinetic Constants. Natural Selection and Kinetic Constants. High-Affinity and Low-Affinity Transporters. From Black Box Kinetic Models of Regulation to Better Defined Mechanisms of Transport Regulation. Molecular Basis of Nutrient Homeostasis. Potassium. Phosphate. Sulfate. Nitrogen. Summary. References. 7: Root Architecture and Nutrient Acquisition. Introduction. Architectural Types. Classes of Nutrient Resources. Intrinsic and Extrinsic Roles of Root Architecture. in Nutrient Acquisition. Intrinsic Roles of Root Architecture in Nutrient Acquisition. Efficiency of Vascular Networks. Dispersal or Root Foraging. Structure of Root Demographics. The Importance of Scale. Extrinsic Roles of Root Architecture in Nutrient Acquisition. Exploiting a Non-uniform Environment. Interaction with Soil Organisms. Competition Among Plants. Practical Applications. The Agroecology of Root Architecture -Improving Crop Nutrient Efficiency. Understanding and Managing Global Change. Future Prospects. Summary. References. 8: The Efficiency of Nutrient Acquisition over the Life of a Root. Introduction. Root Length and Absorptive Surface Area. Importance. Inconsistencies Between Root Length, Mycorrhizal Colonization and Observed Nutrient Uptake. Root Architecture and Variation Among Fibrous Rootsin a Single Root System. Variation in Root Life Span in Different Environments and Among Species. Costs of Root Production and Maintenance. over a Root's Lifetime. Biomass Costs of Producing Root Absorptive Surface Area. Root:Shoot Biomass Partitioning. Specific Root Length. Root Hairs and Mycorrhizal Hyphae. Costs of Root Respiration. Construction Cost and Growth Respiration. Maintenance Respiration. Ion-Uptake Respiration. Cost of Mycorrhizal Colonization and Maintenance. Changes in C Costs as the Root Ages. Other Costs. Uptake of Mineral Nutrients over a Root's Lifetime. Initial Advantages to Root Growth. Importance of Mycorrhizal Colonization. Longevity of Root Tissues. Overview. Longevity of Root Hairs and Epidermis. Longevity of Cortex. Longevity of Xylem Vessels. Changes in Nutrient Uptake Capacity as the Root Ages. The Efficiency of Nutrient Acquisition over a Root's Lifetime. Efficiency Concepts and Model Simulations. Problems Associated with Efficiency. Efficiency Versus Effectiveness. Problems of Currency. Heterogeneous Soil. Overview. Effects of Water and Temperature. Effects of Nutrient-Rich Patches. Summary. References. 9: Action and Interaction in the Mycorrhizal Hyphosphere -a Reevaluation of the Role of Mycorrhizas in Nutrient Acquisition and Plant Ecology. Introduction. Mycorrhizal Symbiosis and Its Quantitative Effects on Plant Nutrition. Mycorrhizal Symbiosis - an Overview. Mycorrhizal Mycelia as Physical Extensions of Root Systems Qualitative Effects of Mycorrhizal Interactions with the Abiotic Environment. Uptake and Utilisation of Organic Nutrients. Weathering and Acquisition of Poorly Soluble Minerals. Biotic Interactions. Interactions with Bacteria. Interactions with Fungi. Interactions with Other Soil Organisms. Multiplicity of Function - Non-nutritional Roles. Implications for Nutrient Cycling and Plant Ecology. Practical Implications of Mycorrhizosphere Effects. Concluding Remarks. Summary. References. 10: Effects of Soil Temperature on Nutrient Uptake. Introduction. Dynamics of Soil Temperature. The Soil Energy Balance. Spatial and Temporal Variation in Soil Temperature. Soil Temperature Effects on Soil Physical and Chemical Properties. Soil Water. Nutrient Transport. Chemical Reactions. Soil Temperature Effects on Root Biology. Root Growth and Morphology. Root Physiology. Soil Temperature Effects on Soil Biology. Decomposition and Nutrient Mineralization.Soil Fauna. Symbiotic Relationships. Summary and Areas of Future Research. References. Nutrient Acquisition of Terrestrial Plants in a Changing Climate. Introduction. Elevated Tropospheric Ozone or Elevated UV-B Radiation. Extent of the Problem and Relevance to Nutrient Uptake. Direct Effects on Nutrient Uptake. Changes in Root-to-shoot Ratios, Morphology and Architecture. Changes in Root Respiration and Carbohydrate Supply to the Roots. Changes in Root Uptake Kinetics. Changes in Foliar Uptake/Leaching. Indirect Effects on Nutrient Uptake. Elevated Atmospheric CO2 Concentration. Extent of the Problem and Relevance to Nutrient Uptake. Direct Effects of CO2 on Plant Nutrient Uptake. Changes in Root-to-Shoot Ratios. Changes in Root Morphology and Architecture. Changes in Root Uptake Kinetics. Indirect Effects of CO2 on Nutrient Availability at the Root Surface. Summary. References. 12: From Molecular Biology to Biogeochemistry: Toward an Integrated View of Plant Nutrient Uptake. Introduction. Nutrient Bioavailability. Plant Nutrient Demand and Use Efficiency. Root System Traits That Regulate Nutrient Acquisition. Global Change and Plant Nutrient Acquisition. Broader Issues and Directions for Future Research. References.