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首页> 外文学位 >Comparing arbuscular and ectomycorrhizal fungal communities in seven North American forests and their response to nitrogen fertilization.
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Comparing arbuscular and ectomycorrhizal fungal communities in seven North American forests and their response to nitrogen fertilization.

机译：比较北美七个森林中的丛枝和外生菌根真菌群落及其对氮肥的响应。

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摘要

Mycorrhizal fungi are found extensively in forest soils and play a crucial role in carbon and nitrogen cycling between plant and soil. However, little is known about how mycorrhizal communities differ between forest systems or what role they play in below ground carbon dynamics. This study addresses the basic ecological questions of how ECM and AM vary between gymnosperm and angiosperm host taxa in undisturbed forest ecosystems which vary in climate and soil characteristics. I use a manipulative N fertilization experiment to study the mycorrhizae between forest sites and their role in ecosystem cycling. AM and ECM percent colonized root length and colonized root length per minirhizotron frame differed between sites and between years. The extramatrical hyphae of all four major AM genera were present at all sites whereas spores, in low abundance, were mainly Glomus spp. Richness of ECM morphotypes was similar between sites at a variety of scales. Functional groups based on ECM morphological characters differed between sites and some fertilization effects were found. Site location was the most influential factor in determining mycorrhizal abundance, composition, and overall role in carbon and nitrogen cycling. At the P. edulis site, I intensively studied the abundance, diversity, composition, and spatial distribution of ECM using morphotyping and RFLP analysis. Years differed in ECM abundance and composition. ECM types differed in frequency across the landscape, abundance at any individual tree, and spatial aggregation. Each P. edulis tree was similar in ECM tip abundance, richness, and number of dominant ECM types. At all scales a few ECM types were dominant however there was temporal and tree to tree variability in which ECM were dominant. The individual tree is the most important sampling unit when assessing P. edulis ECM diversity and composition. Also at the P. edulis site, using RFLP analysis to identify ECM types and 14C to estimate age I found a differential response in the 14C signature of RFLP types to N fertilization indicating that N fertilization does not affect all ECM fungi similarly and functional differences in ECM fungi exist.
机译：菌根真菌广泛存在于森林土壤中，并且在植物与土壤之间的碳和氮循环中起着至关重要的作用。但是，人们对菌根群落在森林系统之间的差异或它们在地下碳动态中所起的作用知之甚少。这项研究解决了基本生态问题，即在不受干扰的森林生态系统中，裸子植物和被子植物宿主类群之间的ECM和AM如何变化，森林生态系统的气候和土壤特征各不相同。我使用操纵性施氮实验研究了林地之间的菌根及其在生态系统循环中的作用。每个部位和年份之间，AM和ECM的定殖根长百分比和每个微根管骨架的定殖根长百分比都不同。所有四个主要AM属的基质外菌丝都存在于所有部位，而孢子的丰度较低，主要是 Glomus spp。在各种规模的站点之间，ECM形态类型的丰富程度相似。基于ECM形态特征的官能团在位点之间有所不同，并且发现了一些施肥作用。站点位置是确定菌根丰度，组成以及碳氮循环中总体作用的最重要因素。在 P。我通过形态分型和RFLP分析深入研究了ECM的丰度，多样性，组成和空间分布。 ECM的丰度和组成各年不同。 ECM类型在整个景观中的频率，任何一棵树的丰度和空间聚集的频率都不同。每个 P。可食树在ECM尖端丰度，丰富度和主要ECM类型数量上相似。在所有尺度上，少数ECM类型占主导地位，但是在ECM占主导地位的时间和树与树之间存在可变性。评估

时，单个树是最重要的采样单位。食用菌ECM的多样性和组成。同样在 P。食用，通过RFLP分析来识别ECM类型，并使用14C来估计年龄，我发现RFLP类型的14C签名对氮肥的反应不同，这表明氮肥不会类似地影响所有ECM真菌和ECM的功能差异真菌存在。

著录项

  • 作者

    Lansing, Jennifer Lyn.;

  • 作者单位

    University of California, Davis.;

  • 授予单位 University of California, Davis.;
  • 学科 Biology Ecology.; Agriculture Forestry and Wildlife.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 156 p.
  • 总页数 156
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生态学（生物生态学）;森林生物学;
  • 关键词

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