e-journal

Evidence that Northern Pioneering Pines with Tuberculate Mycorrhizae are Unaffected by Varying Soil Nitrogen Levels

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Abstract
Tuberculate mycorrhizae on Pinus contorta (lodgepole pine) have previously been shown to reduce
acetylene, but an outstanding question has been to what degree these structures could meet the nitrogen requirements of the tree. We compared the growth, tissue nitrogen contents, and stable nitrogen isotope ratios of P. contorta growing in gravel pits to the same species growing on adjacent
intact soil. Trees growing in severely nitrogen deficient gravel pits had virtually identical growth rates and tissue nitrogen contents to those growing on intact soil that had nitrogen levels typical for the area. δ15N values for trees in the gravel pits were substantially lower than δ15N values for
trees on intact soil, and isotope ratios in vegetation were lower than the isotope ratios of the soil. The form of soil nitrogen in the gravel pits was almost exclusively nitrate, while ammonium predominated in the intact soil. Discrimination against 15N during plant uptake of soil nitrate in the
highly N-deficient soil should be weak or nonexistent. Therefore, the low δ15N in the gravel pit trees suggests that trees growing in gravel pits were using another nitrogen source in addition to the soil. Precipitation-borne nitrogen in the study area is extremely low. In conjunction with our other work, these findings strongly suggests that P. contorta and its microbial symbionts or associates fix nitrogen in sufficient amounts to sustain vigorous tree growth on the most nitrogen-deficient soils.

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Ketersediaan

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Informasi Detail

Judul Seri

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No. Panggil

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Penerbit

: Springer-Verlag., 2012

Deskripsi Fisik

Microb Ecol (2012) 64:964–972 DOI 10.1007/s00248-012-0076-0

Bahasa

English

ISBN/ISSN

1432-184X

Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

EKOLOGI
MIKROBIOLOGI

Info Detail Spesifik

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Pernyataan Tanggungjawab

ETY

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