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

在草原上，高达80%的植物群以根的形式存在于地下。根在决定植物群落的物种组成和多样性方面起着重要作用。植物之间对资源的竞争是塑造植物群落的驱动力，而根系竞争往往比地上竞争具有更强的影响。根竞争研究的最新综述认为，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。该项目通过确定根系生长如何响应植物在土壤中遇到的两个重要线索来研究根系相互作用的机制：养分的可用性和竞争对手的根的存在。本研究将探讨根系生长反应如何影响竞争与群落结构。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的原理。根在土壤中遇到许多线索，这些线索可能引发生长模式的变化，以最大限度地提高植物的适应性。这项研究集中在两个线索，是很好的研究，但仍然没有完全理解：营养丰富的补丁，和邻居的根。这些线索的反应将研究一组8个共同发生的草原植物物种。个体将生长在具有均匀或不均匀分布的资源的土壤中，并且在存在或不存在邻居的情况下，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。将使用一组物种特异性DNA标记来确定来自两个物种盆的样品中的根的物种身份和相对丰度。在第二个实验中，七个或八个物种的群落将在温室微观世界中生长，以确定物种的反应特征是否影响群落结构或幼苗在现有植被中建立的能力。此外，还将制定根系生长的课堂调查方法，植物生长在透明的塑料容器中，以便容易观察和测量根系。非理科专业生态学课程的学生将使用该系统练习科学方法，同时询问有关本地和非本地物种根系生长的问题。

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.