International Research Fellowship Program: Herbivorous Nematodes and the Microbial Loop: Unraveling Below-ground Mechanisms Affecting Plant Production

国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将支持Jennifer A.Kruins博士与荷兰赫特伦荷兰生态研究所的Wim H.van der Putten博士合作的为期18个月的研究奖学金。土壤食物网中的营养循环对植物生产和植物群落多样性至关重要，因为土壤有机体(特别是微生物环)之间的直接和间接相互作用可能会影响植物的养分供应。大多数土壤研究研究的是与植物根相关的土壤食物网中的微生物与其他生物隔离进行的营养循环。在自然界中，植物和土壤有机体之间的正反馈和负反馈的混合推动了养分循环，并最终推动了植物生产和群落结构。例如，线虫放牧根部可能会对植物产生负面影响(直接影响)，但与放牧相关的消费废物可能会通过营养丰富对植物产生积极影响(间接影响)。这个与van der Putten博士合作开发的奖学金项目的目标是将这些间接(养分转化)和直接(草食性动物)相互作用整合到土壤群落中。通过这样做，他们不仅将解决决定植物产量的重要地下机制，而且还将有助于建立一个重要的理论体系，描述植物与土壤生物群之间正向和负向相互作用的相对重要性。这里提出的实验将同时回答以下重要问题：1)根部食草性是否会对微生物群落生物量和活性产生间接的正向影响？微生物环活性增强会对植物生产产生积极影响吗？他们将在使用盆栽沙丘草的温室实验中解决这些问题。为了测试放牧的直接影响，PI将创建一个食草性线虫密度梯度，并测量功能和群落组成方面的微生物循环响应，以及地下和地上生物量的植物响应。通过与Peter C.de Ruiter博士和主持人的合作，在这些实验中获得的数据将被用来开发预测植物对间接正反馈的反应的数学模型。

0758674KruminsThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support an eighteen-month research fellowship by Dr. Jennifer A. Krumins to work with Dr. Wim H. van der Putten at the Netherlands Institute of Ecology in Heteren, The Netherlands.Nutrient cycling in soil food webs is critical to plant production and plant community diversity because direct and indirect interactions between soil organisms (especially the microbial loop) potentially affect nutrient availability to plants. Most soil research studies nutrient cycling carried out by microbes in isolation from other organisms in soil food webs associated with plant roots. In nature, a mixture of positive and negative feedbacks between plants and soil organisms drive nutrient cycling and ultimately, plant production and community structure. For instance, root grazing by nematodes can negatively affect plants (a direct effect), but consumer waste associated with grazing may positively affect plants through nutrient enrichment (an indirect effect). The goal of this fellowship project, developed in collaboration with Dr. van der Putten, is to integrate these indirect (nutrient conversion) and direct (herbivorous animals) interactions in the soil community. In doing this, they will not only resolve important below-ground mechanisms that determine plant production, but will also contribute to an important growing body of theory describing the relative importance of positive versus negative interactions between plants and soil biota. The experiment proposed here will simultaneously answer the following important questions: 1.) Will root herbivory indirectly and positively affect microbial loop biomass and activity? 2.) Will enhanced microbial loop activity positively influence plant production? They will address these questions in greenhouse experiments using potted dune grasses. To test the direct effect of grazing, the PI will create an herbivorous nematode density gradient and measure microbial loop response in function and community composition and plant response in below and above ground biomass. Through collaboration with Dr. Peter C. de Ruiter and the host, the data acquired in these experiments will be used to develop mathematical models predicting plant responses to indirect, positive feedbacks.