Effect of Fungal Endophyte Infection on the Structure of Experimental Grasslands

粘土97 27116生物相互作用长期以来一直是生态学研究的热点，特别是考虑到它们在影响生态系统过程中与多样性的相互作用。这种相互作用中更广泛和潜在重要的一种是生活在它们细胞内的草和真菌之间的共生。在这个项目中，PI，Keith Clay，将利用内生真菌和高羊茅之间的联系，高羊茅是一种常见于草原的物种。这种特殊的联系在高羊茅中是不寻常的，高羊茅出现在有或没有真菌内生菌的菌株中。这项研究将在实验测试中操纵这两种形式的共生体对这一草种的潜在好处。调查将评估真菌内生真菌感染如何影响高羊茅草原的多样性和产量。他们还将评估对草食和胁迫的抗性在多大程度上影响受内生真菌感染的草的优势。一系列的地块将种植内生菌和非内生菌感染的草菌株的种子，以检查它们对植物多样性和产量的影响。围栏和杀虫剂的使用将被用来改变草食的水平，并将量化存活的感染和未感染的草种的相对比例。生态边缘的地点也将种植这两个菌株以及其他四个羊茅品种，以检查它们的总体成功率。这项工作的最终目标将是研究微生物共生在植物群落结构和功能中的一般作用。这项工作将提供重要的实用信息，因为高羊茅是美国东部草原上的优势物种之一。

Clay 97 27116 Biotic interactions have long been of considerable interest in ecology particularly in light of their interactions with diversity in influencing ecosystem processes. One of the more widespread and potentially important of such interactions is the symbiosis occurring between grasses and fungi that live within their cells. In this project, the PI, Keith Clay, will take advantage of an association between endophytic fungi and tall fescue, Festuca arundinacea, a species that occurs commonly in grasslands. This particular association is unusual in Festuca arundinacea occurs in strains that do or do not have fungal endophytes. This research will manipulate these two forms in experimental tests of the potential benefits of the symbionts for this grass species. Investigations will evaluate how fungal endophyte infections influence the diversity and production of Festuca arundinacea grasslands. They will also evaluate the degree to which resistance to herbivory and stress influence the dominance of endophyte-infected grasses. A series of plots will be planted with seeds of endophyte- and non-endophyte infected grass strains to examine their effects on plant diversity and production. Fencing and insecticide applications will be used to vary the levels of herbivory and the relative proportions of infected and noninfected grass strains that survive will be quantified. Ecologically marginal sites will also be planted with the two strains as well as four other fescue species to examine their overall success rates. The ultimate goal of this work will be to examine general role of microbial symbiosis in the structure and function of plant communities. This work will provide important practical information because tall fescue is one of the dominant species across the eastern US in grasslands.