Dissertation Research: Nitrogen and Water Utilization by Co-occurring Evergreen Oak that Differ in Rooting Depth

不同土壤水分和氮素吸收利用模式 两种生长在蛇纹土壤上的橡树， 研究了 初步结果表明， agrifolia和Q. durata在生根深度不同， 土壤中的水和氮的有效性随两者而变化。 深度和季节 据推测，由于 土壤资源有效性与根系空间相互作用 分布，Q. durata和Q. agrifolia可以获得不同水平的氮和水。 据进一步预测，这两个相邻的个体 不同的物种应该在获取和利用 氮和水。 这些假设将使用 现场和受控环境研究。 信息 生根深度将与水的可用性进行比较， 氮在几个深度。 氮的季节分布 以及几套取水和用水系统， 将遵循相邻大小匹配的植物， 其中Q。durata和Q.对氮和水的适应 可用性将通过种植植物进行调查， 营养沙培条件，旨在模拟 浅根和深根植物可利用的资源。

The patterns of water and nitrogen acquisition and utilization by two species of oaks growing on serpentine-derived soil will be investigated. Preliminary results indicate that Quercus agrifolia and Q. durata differ in rooting depth, and that the availability of water and nitrogen in the soil varies with both depth and season. It is hypothesized that, as a result of spatial interactions between soil resource availability and root distribution, neighboring individuals of Q. durata and Q. agrifolia have access to different levels of nitrogen and water. It is further predicted that neighboring individuals of the two species should differ in the acquisition and utilization of nitrogen and water. These hypotheses will be investigated using both field and controlled environment studies. Information on rooting depth will be compared with the availability of water and nitrogen at several depths. The seasonal patterns of nitrogen and water acquisition and utilization for several sets of adjacent size matched plants will be followed, and the ways in which Q. durata and Q. agrifolia acclimate to nitrogen and water availability will be investigated by growing plants under nutrient sand-culture conditions designed to simulate the resources available to shallowly and deeply rooted plants.