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15 N and 13 C natural abundance of autotrophic and myco‐heterotrophic orchids provides insight into nitrogen and carbon gain from fungal association
Author(s) -
Gebauer G.,
Meyer M.
Publication year - 2003
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2003.00872.x
Subject(s) - autotroph , heterotroph , biology , botany , abundance (ecology) , nitrogen , δ13c , isotopes of nitrogen , stable isotope ratio , ecology , bacteria , chemistry , genetics , physics , organic chemistry , quantum mechanics
Summary• Whereas mycorrhizal fungi are acknowledged to be the sources of nitrogen (N) and carbon (C) in achlorophyllous (myco‐heterotrophic) orchids, the sources of these elements in autotrophic orchids are unknown. We have determined the stable isotope abundance of N and C to quantify their gain from different sources in these two functional groups and in non‐orchids of distinctive mycorrhizal types. • Leaves of each plant were collected from four forest and four grassland sites in Europe. The N and C isotope abundance, and total N concentrations of their tissues and of associated soils were determined. • Myco‐heterotrophic orchids were significantly more enriched in 15 N (ɛ MHO‐R = 11.5‰) and 13 C (ɛ MHO‐R = 8.4‰) than co‐occurring non‐orchids. δ 15 N and δ 13 C signatures of autotrophic orchids ranged from values typical of non‐orchids to those more representative of myco‐heterotrophic orchids. • Utilization of fungi‐derived N and C probably explains the relative 15 N and 13 C enrichment in the myco‐heterotrophs. A linear two‐source isotopic mixing model was used to estimate N and C gain of autotrophic orchids from their fungal associates. Of the putatively autotrophic species, Cephalanthera damasonium obtained the most N and C by the fungal route, but several other species also fell into the partially myco‐heterotrophic category.