Record ID No. |
276 |
Author(s) |
Gebauer G., Meyer M. , 2003 |
Affiliation |
University Bayreuth, Lehrstuhl Pflanzenokol, POB 101251, D-95440 Bayreuth, Germany |
Title |
N-15 and C-13 natural abundance of autotrophic and mycoheterotrophic orchids provides insight into nitrogen and carbon gain from fungal association |
Source. Vol.(no):Page |
New Phytologist. 160(1): 209-223p. |
Categories |
Orchid Mycorrhiza |
Subjects |
Physiology |
Host |
n.a. |
Organism |
n.a. |
Country |
Germany, Europe |
Abstracts |
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 N-15 (epsilon(MHO-R) 11.5parts per thousand) and C-13 (epsilon(MHO-R) = 8.4%.) than co-occurring non-orchids. Delta(15)N and delta(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 N-15 and C-13 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 |