Population Dynamics of Rhizosphere Diazotroph Assemblages - Effects of Host and Environmental Variables

生态系统中营养物质的供应和再生通常受到微生物群落的强烈影响。这些过程尤其会受到环境压力的影响。盐沼生态系统的盐度条件导致环境胁迫频繁发生，美国东部沼泽的优势植物互花米草表现出与盐分条件变化相关的独特的生长方式。这项提议将检验盐沼中植物生长形式的变化是由盐分引起的细菌固氮的变化所介导的，细菌固氮是根区的一个关键微生物过程。该项目将使用分子生物学技术来检测根区固氮细菌对关键环境压力的反应。它将通过评估东海岸互花链霉菌发生的北部和南部边界附近的地点来检验其发现的一般性。它将为固氮细菌组合对环境胁迫的反应提供一般的见解。

Lovell9903623The supply and regeneration of nutrients in ecosystems are usually strongly influenced by microbial communities. These processes can be particularly affected by environmental stress. The salinity conditions in salt marsh ecosystems generate frequent occurrences of environmental stress and the dominant plant species in eastern US marshes, Spartina alterniflora, exhibits distinct patterns of growth forms that are correlated with changing salt conditions. This proposal will test the notion that the changes in plant growth form in salt marshes are mediated by salinity induced shifts in bacterial N fixation, a critical microbial process in the root zone. The project will employ molecular biological techniques to examine the response of root-zone, N-fixing bacteria to key environmental stresses. It will examine the generality of its findings by evaluating sites near the northern and southern limits of east coast S. alterniflora occurrence. It will provide general insights into the responses of N-fixing bacterial assemblages to environmental stress.