Biotic Interactions of Grassland Plants: Above- and Belowground Linkages

HartnettDEB 9873654植物与菌根真菌之间的共生是广泛存在的重要生态现象，人们对此知之甚少。这些互惠互利的关系可以以各种方式影响合作伙伴，特别是影响植物寄主的食草性。在草原生态系统中，这些关系无处不在，它们对草食的影响可能是通过影响植物对草食的耐受性来发挥作用，而不是简单地提供防御。本项目将综合考虑食草性、植物耐受性和菌根共生来评价食草动物、真菌和寄主植物之间的相互作用。它检验了一般假设，即植物/真菌共生的成本/收益平衡会因栖息地中草食性的数量而改变，菌根真菌影响草食性寄主植物的耐受性和防御。它将在Konza草原研究自然区进行的一系列Tallgras草原中围隔和野外实验中检验这些假说，以检验光、N和P三种不同潜在限制资源的一般影响。这项工作将进一步理解草食动物、真菌互惠共生体和寄主植物在草原生态系统中完成重要生物相互作用的角色和相互作用。它将增加对植物-真菌互惠关系的理解，特别是通过评估第三方--草食动物--对共生体稳定性的制约。

HartnettDEB 9873654Symbioses between plants and mycorrhizal fungi are wide-spread, ecologically important phenomena that are poorly understood. These mutualistic relationships can affect the partners in a variety of ways particularly influencing herbivory on the plant hosts. In grassland ecosystems where these relationships are ubiquitous, their influence on herbivory may operate by affecting plant tolerance of herbivory rather than simply providing defense against it. This project will integrate considerations of herbivory, plant tolerace and mycorrhizal symbiosis in evaluating ineractions between herbivores, fungi and host plants. It tests the general hypotheses that the cost/benefit balance of plant/fungal symbioses are altered by the amount of herbivory in a habitat and that mycorrhizal fungi influence the tolerance and defenses of host plants of herbivores. It will test these hypotheses in a series of tallgrass prairie mesocosm and field experiments that are being conducted at the Konza Prairie Research Natural Area to examine the general influence of three different potentially limiting resources, light, N and P. This work wil further the understanding of the roles and interactions of hervivores, fungal mutualists, and host plants which accomplish important biotic interactions in grassland ecosystems. It will increase the understanding of plant-fungal mutualism, particularly by evaluating the constraints of a third party, a herbivore, on the stability of the symbioses.