DISSERTATION RESEARCH: Do Common Mycorrhizal Networks Limit Plant Competition and Species Exclusion in Temperate Forests?

摘要论文研究：共同的菌根网络限制植物竞争和物种排斥在温带森林？在自然界中，菌根真菌网络包围并连接相邻植物的根，通常包括几平方米的多个物种。 温室实验表明，当相邻植物被遮挡或氮浓度较低时，幼苗获得的碳和氮通过这些共同的菌根网络（CMN）定向迁移到相邻植物中。 据推测，CMN限制竞争，特别是在上层和招募树木种群之间，并对森林群落结构产生间接影响。 本研究将1）证明CMN对生长在温带森林中的三种树木幼苗的生长和存活的重要性，2）评估CMN对幼苗物种性能等级的影响，3）量化菌根宿主特异性和田间种间CMN的频率，4）阐明CMN将土壤N分配给多个宿主的规则。 另一项研究将首次利用13-C同位素分析证明上层树木和幼苗之间的碳流动。 这项研究将有助于解释CMN对幼苗表现的影响，并为我们理解森林生态系统中的菌根功能，植物竞争和演替做出重大贡献。

AbstractDISSERTATION RESEARCH: Do Common Mycorrhizal Networks Limit Plant Competition and Species Exclusion in Temperate Forests?SchmitzDEB-0309225In nature, networks of mycorrhizal fungi encompass and connect the roots of neighbor plants, often including multiple species over several square meters. Greenhouse experiments show that carbon and nitrogen acquired by seedlings move directionally into neighbors via these common mycorrhizal networks (CMN) when neighbors are shaded or have low N concentration. It has been hypothesized that CMN limit competition, particularly between overstory and recruiting tree populations, and have indirect effects on forest community structure. This research will 1) demonstrate the importance of CMN for the growth and survival of three tree seedling species growing in a temperate forest, 2) evaluate the influence of CMN on the hierarchy of seedling species performance, 3) quantify mycorrhizal host-specificity and the frequency of interspecific CMN in the field, and 4) clarify the rules that govern the distribution of soil N to multiple hosts by CMN. An additional study will demonstrate, for the first time, carbon flow between overstory trees and seedlings using13-C isotope analysis. This study will aid in interpretation of CMN effects on seedling performance, and stand as a major contribution to our understanding of mycorrhizal functioning, plant competition, and succession in forest ecosystems.