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Article Dans Une Revue New Phytologist Année : 2005

Mixotrophy in orchids: insights from a comparative study of green individuals and nonphotosynthetic individuals of Cephalanthera damasonium

Thomas Julou
  • Fonction : Auteur
Bastian Burghardt
  • Fonction : Auteur
Gerhard Gebauer
  • Fonction : Auteur
Daniel Berveiller
Marc‐andré Selosse
  • Fonction : Auteur

Résumé

• Some green orchids obtain carbon (C) from their mycorrhizal fungi and photosynthesis. This mixotrophy may represent an evolutionary step towards mycoheterotrophic plants fully feeding on fungal C. Here, we report on nonphotosynthetic individuals (albinos) of the green Cephalanthera damasonium that likely represent another evolutionary step. • Albino and green individuals from a French population were compared for morphology and fertility, photosynthetic abilities, fungal partners (using microscopy and molecular tools), and nutrient sources (as characterized by 15 N and 13 C abundances). • Albinos did not differ significantly from green individuals in morphology and fertility, but tended to be smaller. They harboured similar fungi, with Thelephoraceae and Cortinariaceae as mycorrhizal partners and few rhizoctonias. Albinos were nonphotosynthetic, fully mycoheterotrophic. Green individuals carried out photosynthesis at compensation point and received almost 50% of their C from fungi. Orchid fungi also colonized surrounding tree roots, likely to be the ultimate C source. • Transition to mycoheterotrophy may require several simultaneous adaptations; albinos, by lacking some of them, may have reduced ecological success. This may limit the appearance of cheaters in mycorrhizal networks.

Dates et versions

hal-03991039 , version 1 (20-10-2023)

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Citer

Thomas Julou, Bastian Burghardt, Gerhard Gebauer, Daniel Berveiller, Claire Damesin, et al.. Mixotrophy in orchids: insights from a comparative study of green individuals and nonphotosynthetic individuals of Cephalanthera damasonium. New Phytologist, 2005, 166 (2), pp.639-653. ⟨10.1111/j.1469-8137.2005.01364.x⟩. ⟨hal-03991039⟩
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