Substantial nitrogen acquisition by arbuscular mycorrhizal fungi from organic material has implications for N cycling.
نویسندگان
چکیده
Arbuscular mycorrhizal (AM) fungi are obligate biotrophs that acquire carbon (C) solely from host plants. AM fungi can proliferate hyphae in, and acquire nitrogen (N) from, organic matter. Although they can transfer some of that N to plants, we tested the hypothesis that organic matter is an important N source for the AM fungi themselves. We grew pairs of plants with and without the AM fungus Glomus hoi in microcosms that allowed only the fungus access to a 15N/13C-labeled organic patch; in some cases, one plant was shaded to reduce C supply to the fungus. The fungal hyphae proliferated vigorously in the patch, irrespective of shading, and increased plant growth and N content; approximately 3% of plant N came from the patch. The extraradical mycelium of the fungus was N-rich (3-5% N) and up to 31% of fungal N came from the patch, confirming the hypothesis. The fungus acquired N as decomposition products, because hyphae were not 13C-enriched. In a second experiment, hyphae of both G. hoi and Glomus mosseae that exploited an organic material patch were also better able to colonize a new host plant, demonstrating a fungal growth response. These findings show that AM fungi can obtain substantial amounts of N from decomposing organic materials and can enhance their fitness as a result. The large biomass and high N demand of AM fungi means that they represent a global N pool equivalent in magnitude to fine roots and play a substantial and hitherto overlooked role in the nitrogen cycle.
منابع مشابه
Phosphorus cycling in deciduous forest soil differs between stands dominated by ecto- and arbuscular mycorrhizal trees.
Although much is known about how trees and their associated microbes influence nitrogen cycling in temperate forest soils, less is known about biotic controls over phosphorus (P) cycling. Given that mycorrhizal fungi are instrumental for P acquisition and that the two dominant associations - arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi - possess different strategies for acquiring...
متن کاملThe brighter side of soils: quantum dots track organic nitrogen through fungi and plants.
Soil microorganisms mediate many nutrient transformations that are central in terrestrial cycling of carbon and nitrogen. However, uptake of organic nutrients by microorganisms is difficult to study in natural systems. We assessed quantum dots (fluorescent nanoscale semiconductors) as a new tool to observe uptake and translocation of organic nitrogen by fungi and plants. We conjugated quantum d...
متن کاملResolving the ‘nitrogen paradox’ of arbuscular mycorrhizas: fertilization with organic matter brings considerable benefits for plant nutrition and growth
Arbuscular mycorrhizal fungi (AMF) can transfer nitrogen (N) to host plants, but the ecological relevance is debated, as total plant N and biomass do not generally increase. The extent to which the symbiosis is mutually beneficial is thought to rely on the stoichiometry of N, phosphorus (P) and carbon (C) availability. While inorganic N fertilization has been shown to elicit strong mutualism, c...
متن کاملMycorrhizal phosphorus economies: a field test of the MANE framework.
The conquest of the land by plants, c. 470 million years ago, was made possible by the arbuscular mycorrhizal symbiosis (Selosse et al., 2015). In fact, the evolution of that symbiosis was so successful that plant roots have to fit into an arbuscularmycorrhizal world. But that conclusion at the same time hides a paradox. If the arbuscular mycorrhizal symbiosis was so successful, which empty nic...
متن کاملEffect of biochar on nitrogen retention in soil under corn plant inoculated with arbuscular mycorrhizal fungi
Maintaining the levels of nitrogen in agricultural fields to ensure crop yield performance is challenging due to the complex dynamics of nitrogen transformation in soil. Nitrogen is mainly taken up by plant roots in the form of nitrate, but it is considered as an environmental pollutant that threatens human and animal health. Therefore, it is necessary to use adsorbent compounds to retain nitra...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 107 31 شماره
صفحات -
تاریخ انتشار 2010