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Universität Bayreuth BayCEER – Labor für Isotopen-Biogeochemie SS 2007

Universität Bayreuth BayCEER – Labor für Isotopen-Biogeochemie SS 2007 Modul: Stabile Isotope in der Biogeochemie Vorlesung Stabile Isotope in der Ökologie Lehrperson: Gerhard Gebauer Termin: Do. 8 - 10 Uhr Raum: S 37. Stabile Isotope in der Ökologie.

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Universität Bayreuth BayCEER – Labor für Isotopen-Biogeochemie SS 2007

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  1. Universität Bayreuth BayCEER – Labor für Isotopen-Biogeochemie SS 2007 Modul: Stabile Isotope in der Biogeochemie Vorlesung Stabile Isotope in der Ökologie Lehrperson: Gerhard Gebauer Termin: Do. 8 - 10 Uhr Raum: S 37

  2. Stabile Isotope in der Ökologie • Inhalt der Vorlesung (II): • Stickstoffisotope: • N-Quellen für Pflanzen (substanzspezifische und räumliche Variation im • Isotopenverhältnis, Wirkung anthropogener Einflüsse) • Aufnahme bodenbürtiger N-Quellen (Ammonium, Nitrat, organ. N) • Rolle der Pilze im N-Kreislauf • mykoheterotrophe Pflanzen • Aufnahme atmosphärischer N-Depositionen und Wirkung auf den N-Haushalt • Nitrataustrag aus Ökosystemen • Lachgasproduktion und -konsumption • Symbiontische N2-Fixierung • N-Ernährung insektenfangender Pflanzen • Isotopenverschiebung bei Nahrungsketten

  3. Mykorrhizaformen und beteiligte Symbiosepartner St = gebündelte Myzelstränge APH = äussere Pilzhülle HN = Hartig´sches Netz IN = Interzelluläres Mycelnetz IK = Intrazelluläres Mycelknäuel V = Pilzvesikel A = Arbuskel SP = Spore Nach Gianinazzi und Gianinazzi-Pearson (1988) aus: Larcher: Ökophysiologie der Pflanzen, 6. Auflage, 2001

  4. From: Schulze, Chapin and Gebauer (1994) Oecologia 100: 406-412

  5. From: Michelsen, Quarmby, Sleep and Jonasson (1998) Oecologia 115: 406-418

  6. Frequencies From: Gebauer and Dietrich (1993) Isotopenpraxis Environ. Health Stud. 29: 35-44

  7. Fichtelgebirge Sept. 1989 Frequencies From: Gebauer and Dietrich (1993) Isotopenpraxis Environ. Health Stud. 29: 35-44

  8. From: Schmidt and Gleixner (1997) In: Griffiths (ed) Stable Isotopes: Integration of Biological, Ecological and Geochemical Processes

  9. Russula ochroleuca Laccaria laccata Cystoderma amianthinum Trametes versicolor + Calocera viscosa

  10. Strobilurus esculentus Micromphale perforans

  11. From: Gebauer and Taylor (1999) New Phytol. 142: 93 -101

  12. From: Gebauer and Taylor (1999) New Phytol. 142: 93 -101

  13. Relation between d15 N values of fungal fruit bodies and of the substrates for their mycelium

  14. Partial mycoheterotrophy – A novel nutritional mode of forest ground vegetation

  15. The forest ground: a light-limited site for plant growth • Light availability in Central European forests at the ground related to the insolation above the canopy: • Pine forest ca. 20 % • Oak forest ca. 10 % • Beech forest ca. 1 – 5 %

  16. Ectomycorrhiza of forest trees Fungal hyphae Fungal partners Hardly cultivable basidiomycetae and ascomycetae, (obligatory ectomycorrhizal fungi) Fungal partners Easily cultivable, saprotrophic basidiomycetae of the Rhizoctonia group Fungal hyphae Endomycorrhiza of orchids

  17. Benefit of the mycorrhiza for plants and fungi Ectomycorrhiza of forest trees CO2 Photosynthesis Carbohydrates ECM fungi Tree Mineral nutrients Water Exoenzymes N assimilation Soil Nitrate, ammonium CO2 Endomycorrhiza of green orchids Photosynthesis ? ? ? Green orchid Saprotrophic fungi Mineral nutrients Water (Carbohydrates) N assimilation Exoenzymes Soil Nitrate, ammonium

  18. Monotropa hypopitys Examples of mycoheterotrophic plants from European forests Neottia nidus-avis

  19. Relative enrichment in heavy isotopes (eMH-R) of mycoheterotrophic orchids (MHO), monotropoids (MHM) and pyroloids (MHP)

  20. Are green orchids really autotrophic? Cephalanthera damasonium Cephalanthera rubra

  21. Are green orchids really autotrophic? Epipactis atrorubens Platanthera chlorantha

  22. Data from: Gebauer & Meyer (2003) New Phytol. 160: 209-223 Bidartondo, Burghardt, Gebauer, Bruns & Read (2004) Proc. R. Soc. Lond. B 271: 1799-1806  Non-orchids with ectomycorrhiza  Non-orchids with arbuscular mycorrhiza  Green orchids(group 1)  Green orchids (group 2)  Mycoheterotrophic orchids

  23. Data from: Bidartondo, Burghardt, Gebauer, Bruns & Read (2004) Proc. R. Soc. Lond. B 271: 1799-1806

  24. CO2 Photosynthesis Organ. C Organ. N Mineral nutrients Water Mineral nutrients Water N assimilation Nitrate ammonium Transition from autotrophic to mycoheterotrophic nutrition CO2 Photosynthesis ECM fungus A Carbohydrates Saprotrophic fungi ECM fungus B Orchids Trees Mineral nutrients Water Exoenzymes ECM fungus C Soil N assimilation Exoenzymes Nitrate ammonium Soil

  25. Cephalanthera damasonium Albino varieties among green orchids Albino variety From: Julou, Burghardt, Gebauer, Berveiller, Damesin & Selosse (2005) New Phytol. 166: 639-653 Green individuum

  26. Non-orchids with ectomycorrhiza  Non-orchids with arbuscular mycorrhiza  Green orchids with ectomycorrhiza  Albino variety of green orchids  Ectomycorrhizal fungi From: Julou, Burghardt, Gebauer, Berveiller, Damesin & Selosse (2005) New Phytol. 166: 639-653

  27. Are green pyroloids also partially mycoheterotrophic? Chimaphila umbellata Orthilia secunda

  28. Data from: Zimmer, Hynson, Gebauer, Allen, Allen & Read (2007) New Phytol. 175: 166-175 Forest sites with different light climate (NE Bavaria, Germany)  Reference plants with ectomycorrhiza  Reference plants with arbuscular mycorrhiza  Green Pyroleae  Mycoheterotrophic orchids or Pyroleae

  29. Source B Source A Contribution of source B to plant total C or N [%] Quantifying mycoheterotrophic nutrition

  30. Data from: Gebauer (2005) Rundgespräche der Kommission für Ökologie, Vol. 30, pp 55-67 Zimmer, Hynson, Gebauer, Allen, Allen & Read (2007) New Phytol. 175: 166-175

  31. Conclusions • Partial mycoheterotrophy is a hitherto unknown nutritional • mode of putatively autotrophic forest ground vegetation. • Partial mycoheterotrophy occurs at least in two important • plant families. • Partial mycoheterotrophy is associated with a switch of • fungal partners, that provides a link between ground • vegetation, ectomycorrhizal fungi and forest trees. • C gain from partial mycoheterotrophy is related to plant • species and to light climate. It allows the plants to move • into the deepest shade of forests without competition. • Combining stable isotope data with molecular biological • techniques provides essentially new perspectives in • research on mycorrhizas.

  32. Many thanks for your attention !

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