Mycorrhizal network: a bidirectional pathway between green-leaved terrestrial orchids and pine trees

Area of Science:

• Ecology
• Plant Biology
• Mycology

Background:

• Plant roots can connect through mycorrhizal networks, influencing ecosystem functions.
• Simultaneous bidirectional resource transfer within these networks is debated.

Purpose of the Study:

• To investigate simultaneous bidirectional carbon (C) and nitrogen (N) transfer between terrestrial orchids and pine seedlings via mycorrhizal networks.
• To determine if resource transfer patterns are species-specific.

Main Methods:

• A compartmented system was used to link three orchid species (Cymbidium goeringii, C. goeringii var. serratum, C. faberi) with Pinus yunnanensis seedlings.
• A 13C and 15N dual labeling approach traced simultaneous C and N movement.

Main Results:

• Unidirectional C and N transfer occurred between C. goeringii and pine seedlings.
• Bidirectional C and N transfer was observed between the other two orchid species and pine seedlings.
• Nitrogen transfer showed three distinct patterns: unidirectional, bidirectional with no net transfer, and bidirectional with net transfer to the orchid.

Conclusions:

• Mycorrhizal networks exhibit dynamic, species-specific resource transfer pathways.
• This specificity influences orchid recruitment and nutrient dynamics in forest understories.
• The role of common mycorrhizal networks in resource exchange is more complex than previously understood.