Jackson Louise E, Burger Martin, Cavagnaro Timothy R
Department of Land, Air and Water Resources, University of California, Davis, California 95616, USA.
Annu Rev Plant Biol. 2008;59:341-63. 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.
本综述探讨了土壤氮（N）循环中涉及根系的一些机制过程，以及它们对生态系统中氮保留的生态功能的影响：1）氮运输系统的根系信号通路及反馈抑制，尤其是对硝酸盐（NO₃⁻）吸收的反馈抑制；2）对菌根和根瘤菌/豆科植物共生关系的依赖及其在氮获取方面的权衡；3）影响铵根离子（NH₄⁺）和硝酸盐向根系及土壤微生物供应的土壤因素；4）根际过程，如激发效应和与土壤食物网的相互作用，这些过程增加了氮的循环和保留。通过整合跨尺度和学科界限的这些植物 - 微生物 - 土壤氮过程的信息，我们提出了更好地操纵生态功能和过程的想法，通过这些功能和过程，环境能够满足人类需求，即生态系统服务。重点关注农业系统、自然生态系统中氮沉降的影响以及生态系统对二氧化碳浓度升高的响应。这表明需要采用多尺度方法来增加人类对基于生物的氮供应的依赖。
