자료유형 | 학위논문 |
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서명/저자사항 | Mycorrhizal-Mediated Nutrient Foraging Strategies of Temperate Tree Species. |
개인저자 | Chen, Weile. |
단체저자명 | The Pennsylvania State University. Ecology. |
발행사항 | [S.l.]: The Pennsylvania State University., 2017. |
발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2017. |
형태사항 | 174 p. |
기본자료 저록 | Dissertations Abstracts International 81-01B. Dissertation Abstract International |
ISBN | 9781392335062 |
학위논문주기 | Thesis (Ph.D.)--The Pennsylvania State University, 2017. |
일반주기 |
Source: Dissertations Abstracts International, Volume: 81-01, Section: B.
Publisher info.: Dissertation/Thesis. Advisor: Eissenstat, David. M. |
요약 | Nutrients are distributed heterogeneously in the soil, and nutrient-rich "hotspots" can be the main source of nutrients for trees in many ecosystems. Roots of most plants cooperate with mycorrhizal fungi in nutrient acquisition. The nutrient-rich patches may be actively foraged by symbioses comprising roots and mycorrhizal fungi. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. However, the foraging behaviors of the symbionts are often experimentally uncoupled in previous studies. Compared to the findings in nutrient foraging by roots, the foraging by mycorrhizal hyphae is much less studied. Predictions of nutrient foraging strategies from specific mycorrhizal root traits are often vague. We investigated the nutrient foraging of root and mycorrhizal fungi among common temperate tree species that varied in the thickness of their absorptive roots, including trees associated with arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) fungi. We found when nutrient availability is patchy, thinner root species (e.g., maple, oak) alter their foraging to exploit patches, whereas thicker root species (e.g., tulip poplar, pine) do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees (e.g. maple) produce more roots, whereas EM trees (e.g. oak) produce more mycorrhizal fungal hyphae. We also investigated the concurrent foraging for nutrient hotspots by plant species with diverse root traits in a species-rich forest. We found that thin-root species increase substantially in dominance in the soil nutrient patches when competing with thick-root species. Moreover, EM hyphae strongly proliferated in the nutrient hotspots whereas AM hyphae exhibited only modest proliferation. Lastly, we tried to link plant functional traits with mycorrhizal fungal community structure. We found that root diameter only weakly predicted community structure of mycorrhizal fungi, as well as fungal functional traits such as EM exploration types. Community diversity and functions of mycorrhizal fungi may be more regulated by whole-plant traits than by root morphological traits. Collectively, these results indicate that strategies of nutrient foraging are often complementary among tree species with contrasting mycorrhiza types and root morphologies. These findings can pave the way for a more holistic understanding of root-fungal function, which is critical to plant growth, plant competition, community dynamics and biogeochemical cycles in forested ecosystems. |
일반주제명 | Ecology. |
언어 | 영어 |
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