SG: Connecting root foraging strategies to competitive outcomes and community structure

草原上高达80%的植物以根的形式存在于地下。根在决定植物群落中物种的组成和多样性方面起着重要的作用。植物之间对资源的竞争是形成植物群落的驱动力，根部竞争往往比地上部分竞争具有更强的影响。最近对根竞争研究的综述认为，要了解植物群落结构，我们需要更多地了解植物在地下相互作用的机制。这个项目通过确定植物在土壤中遇到的两个重要线索：养分的有效性和竞争对手的根的存在，来研究根的相互作用的机制。这项研究将研究根系生长反应如何影响竞争和群落结构。一名研究生和三名本科生将参与这项研究，该项目将用于向非理科专业的学生介绍科学研究原理。根在土壤中遇到许多线索，可能会引发生长模式的变化，以最大限度地适应植物。这项研究的重点是两个已经研究得很好但仍未完全理解的线索：营养丰富的斑块和邻居的根。我们将研究一组8种共同出现的草原植物对这些线索的反应。个体将生长在资源分布均匀或斑驳的土壤中，并在有或没有邻居的情况下生长，以确定物种对邻居的反应是否不同，以及对资源的反应是否取决于邻居的存在。将使用一组物种特有的DNA标记来确定来自两个物种的盆栽样本中的物种身份和根的相对丰度。在第二个实验中，将在温室微观世界中种植七到八个物种的群落，以确定物种的反应特征是否会影响群落结构或幼苗在现有植被中建立的能力。此外，还将开发用于课堂调查根生长的方法，将植物生长在透明的塑料容器中，以便可以容易地观察和测量根。在非理科专业的生态课上，学生们将使用这个系统来练习科学方法，同时询问有关本地和非本地物种的根生长的问题。

Up to 80% of the plant mass in a grassland is belowground, in the form of roots. Roots play a substantial role in determining the composition and diversity of species in plant communities. Competition among plants for resources is a driving force in shaping plant communities, and root competition often has stronger effects than aboveground competition. A recent review of root competition research concludes that to understand plant community structure we need to know more about the mechanisms by which plants interact belowground. This project investigates mechanisms of root interactions by determining how root growth responds to two important cues that plants encounter in the soil: nutrient availability and the presence of the roots of competitors. How root growth responses influence competition and community structure will be investigated with this research. A graduate student and three undergraduates will contribute to the research, and this project will be used to introduce non-science majors to the principles of scientific research.Roots encounter many cues in the soil which may trigger changes in growth patterns to maximize plant fitness. This research focuses on two cues that are well studied but still not fully understood: nutrient-rich patches, and roots of neighbors. Responses to these cues will be studied for a set of eight co-occurring grassland plant species. Individuals will be grown in soil with even or patchy distribution of resources and in the presence or absence of neighbors, to determine whether species differ in response to neighbors and whether responses to resources depend on the presence of neighbors. The species identity and relative abundance of roots in samples from two-species pots will be determined using a set of species-specific DNA markers. In a second experiment, communities of seven or eight species will be grown in greenhouse microcosms to determine whether species' response traits influence community structure or the ability of seedlings to establish in existing vegetation. In addition, methods will be developed for classroom investigations of root growth, with plants grown in clear plastic containers so that roots can be readily observed and measured. Students in an ecology class for non-science majors will use this system to practice the scientific method while asking questions about root growth of native and non-native species.