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Photosynthetic Mediterranean meadow orchids feature partial mycoheterotrophy and specific mycorrhizal associations
Author(s) -
Girlanda Mariangela,
Segreto Rossana,
Cafasso Donata,
Liebel Heiko Tobias,
Rodda Michele,
Ercole Enrico,
Cozzolino Salvatore,
Gebauer Gerhard,
Perotto Silvia
Publication year - 2011
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.1000486
Subject(s) - biology , botany , orchidaceae , mediterranean climate , symbiosis , ecology , genetics , bacteria
• Premise of the study: We investigated whether four widespread, photosynthetic Mediterranean meadow orchids ( Ophrys fuciflora , Anacamptis laxiflora , Orchis purpurea , and Serapias vomeracea ) had either nutritional dependency on mycobionts or mycorrhizal fungal specificity. Nonphotosynthetic orchids generally engage in highly specific interactions with fungal symbionts that provide them with organic carbon. By contrast, fully photosynthetic orchids in sunny, meadow habitats have been considered to lack mycorrhizal specificity. • Methods: We performed both culture‐dependent and culture‐independent ITS sequence analysis to identify fungi from orchid roots. By analyzing stable isotope ( 13 C and 15 N) natural abundances, we also determined the degree of autotrophy and mycoheterotrophy in the four orchid species. • Key results: Phylogenetic and multivariate comparisons indicated that Or . purpurea and Oph. fuciflora featured lower fungal diversity and more specific mycobiont spectra than A. laxiflora and S. vomeracea . All orchid species were significantly enriched in 15 N compared with neighboring non‐orchid plants. Orchis purpurea had the most pronounced N gain from fungi and differed from the other orchids in also obtaining C from fungi. • Conclusions: These results indicated that even in sunny Mediterranean meadows, orchids may be mycoheterotrophic, with correlated mycorrhizal fungal specificity.