Roots, Nitrogen Transformations, and Ecosystem Services

• Published in: Annual review of plant biology Vol. 59; pp. 341 - 363
• Main Authors: Jackson, L.E, Burger, M, Cavagnaro, T.R
• Format: Journal Article
• Language: English
• Published: United States 01.01.2008
• Subjects: Air; ammonium nitrogen; atmospheric deposition; biogeochemical cycles; Biological Transport; carbon dioxide; Carbon Dioxide - metabolism; Ecosystem; ecosystem services; elevated atmospheric gases; Fabaceae; Fertilizers; literature reviews; mycorrhizae; mycorrhizal fungi; nitrate nitrogen; nitrogen; Nitrogen - metabolism; nutrient retention; nutrient transport; Plant Development; plant ecology; Plant Roots - metabolism; Plant Roots - physiology; plants; Rhizobiaceae; Rhizome - physiology; rhizosphere; roots; signal transduction; Soil; soil ecology; soil fertility; symbiosis; translocation (plant physiology)
• ISSN: 1543-5008; 1545-2123
• DOI: 10.1146/annurev.arplant.59.032607.092932

This review considers some of the mechanistic processes that involve roots in the soil nitrogen (N) cycle, and their implications for the ecological functions that retain N within ecosystems: 1) root signaling pathways for N transport systems, and feedback inhibition, especially for NO(3)(-) uptake; 2) dependence on the mycorrhizal and Rhizobium/legume symbioses and their tradeoffs for N acquisition; 3) soil factors that influence the supply of NH(4)(+) and NO(3)(-) to roots and soil microbes; and 4) rhizosphere processes that increase N cycling and retention, such as priming effects and interactions with the soil food web. By integrating information on these plant-microbe-soil N processes across scales and disciplinary boundaries, we propose ideas for better manipulating ecological functions and processes by which the environment provides for human needs, i.e., ecosystem services. Emphasis is placed on agricultural systems, effects of N deposition in natural ecosystems, and ecosystem responses to elevated CO(2) concentrations. This shows the need for multiscale approaches to increase human dependence on a biologically based N supply.