Lee, Y-I; Yang, C-K; Gebauer, G: The importance of associations with saprotrophic non-Rhizoctonia fungi among fully mycoheterotrophic orchids is currently under-estimated: novel evidence from sub-tropical Asia, Annals of Botany, 116, 423-435 (2015), doi:10.1093/aob/mcv085
Abstract:

Background and Aims Most fully mycoheterotrophic (MH) orchids investigated to date are mycorrhizal with fungi that simultaneously form ectomycorrhizas with forest trees. Only a few MH orchids are currently known to be mycorrhizal with saprotrophic, mostly wood-decomposing, fungi instead of ectomycorrhizal fungi. This study provides evidence that the importance of associations between MH orchids and saprotrophic non-Rhizoctonia fungi is currently under-estimated. 

Methods Using microscopic techniques and molecular approaches, mycorrhizal fungi were localized and identified for seven MH orchid species from four genera and two subfamilies, Vanilloideae and Epidendroideae, growing in four humid and warm sub-tropical forests in Taiwan. Carbon and nitrogen stable isotope natural abundances of MH orchids and autotrophic reference plants were used in order to elucidate the nutritional resources utilized by the orchids. 

Key Results Six out of the seven MH orchid species were mycorrhizal with either wood- or litter-decaying saprotrophic fungi. Only one orchid species was associated with ectomycorrhizal fungi. Stable isotope abundance patterns showed significant distinctions between orchids mycorrhizal with the three groups of fungal hosts. 

Conclusions Mycoheterotrophic orchids utilizing saprotrophic non-Rhizoctonia fungi as a carbon and nutrient source are clearly more frequent than hitherto assumed. On the basis of this kind of nutrition, orchids can thrive in deeply shaded, light-limiting forest understoreys even without support from ectomycorrhizal fungi. Sub-tropical East Asia appears to be a hotspot for orchids mycorrhizal with saprotrophic non-Rhizoctonia fungi.

Upcoming ...


BayCEER Colloquium:
Th. 2017-12-14 now
A Molecular Scale Approach: X-Ray Absorption Spectroscopy in Environmental Study
Th. 2017-12-21
Silicon in biogeochemistry
Ökologisch-Botanischer Garten:
Su. 2018-01-07
Stärk´ anlaufen: Winterspaziergang im ÖBG
Su. 2018-01-07
Musikalischer Jahresbeginn mit den Rockin´ Dinos
Workshop:
Th. 2017-12-14 now
Workshop on synchrotron-based X-ray absorption spectroscopy
Weather research site
Luftdruck (356m): 951.0 hPa
Lufttemperatur: 4.3 °C
Niederschlag: 4.1 mm/24h
Sonnenschein: <1 h/d
Wind (Höhe 17m): 16.6 km/h
Wind (Max.): 32.0 km/h
Windrichtung: SW

...more
Globalstrahlung: 1 W/m²
Lufttemperatur: 0.9 °C
Niederschlag: 2.9 mm/24h
Sonnenschein: <1 h/d
Wind (Höhe 32m): 23.4 km/h
Wind (Max.): 50.4 km/h

...more