Premium
Mutualistic mycorrhiza in orchids: evidence from plant–fungus carbon and nitrogen transfers in the green‐leaved terrestrial orchid Goodyera repens
Author(s) -
Cameron Duncan D.,
Leake Jonathan R.,
Read David J.
Publication year - 2006
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 - 10.1111/j.1469-8137.2006.01767.x
Subject(s) - biology , mycelium , botany , mycorrhiza , repens , fungus , symbiosis , shoot , hypha , ectomycorrhiza , bacteria , genetics
Summary• The roles of mycorrhiza in facilitating the acquisition and transfer of carbon (C) and nitrogen (N) to adult orchids are poorly understood. Here, we employed isotopically labelled sources of C and N to investigate these processes in the green forest orchid, Goodyera repens . • Fungus‐to‐orchid transfers of C and N were measured using mass spectrometry after supplying extraradical mycelial systems with double‐labelled [ 13 C‐ 15 N]glycine. Orchid‐to‐fungus C transfer was revealed and quantified by radioisotope imaging and liquid scintillation counting of extraradical mycelium following 14 CO 2 fixation by shoots. • Both 13 C and 15 N were assimilated by the fungus and transferred to the roots and shoots of the orchid. Contrary to previous reports, considerable quantities (2.6% over 72 h) of fixed C were shown to be allocated to the extraradical mycelium of the fungus. • This study demonstrates, for the first time, mutualism in orchid mycorrhiza, bidirectional transfer of C between a green orchid and its fungal symbiont, and a fungus‐dependent pathway for organic N acquisition by an orchid.