MYCORRHIZAE AND MYCORRHIZAL FUNGI OF CALYPSO BULBOSA

Area of Science:

• Botany
• Mycology
• Orchidology

Background:

• Calypso bulbosa (L.) Oakes is a terrestrial orchid with complex mycorrhizal root associations.
• Understanding fungal endophytes is crucial for orchid life cycle and conservation.

Purpose of the Study:

• To examine the seasonal development of mycorrhizal roots in Calypso bulbosa.
• To identify and characterize the fungal endophytes colonizing these roots.
• To investigate the root morphology, specifically the presence of a coralloid rhizome.

Main Methods:

• Analysis of fresh Calypso bulbosa root collections from Alberta.
• Examination of herbarium specimens from six different herbaria.
• Isolation and identification of fungal endophytes using culturing and morphological analysis.

Main Results:

• Each growing season, typically one pair of mycorrhizal roots develops at the base of a single corm.
• No evidence supported the existence of a coralloid rhizome in Calypso bulbosa.
• Fungal infection, peloton formation, and breakdown patterns resemble those in other terrestrial orchids.
• Multiple fungal taxa, including Rhizoctonia anaticula, Thanatephorus pennatus, Leptodontidium orchidicola, Phialocephala fortinii, and two unnamed Rhizoctonia isolates, were identified within single mycorrhizal roots.

Conclusions:

• Calypso bulbosa exhibits standard mycorrhizal root development and fungal endophyte interactions typical of terrestrial orchids.
• The absence of a coralloid rhizome suggests a unique morphological characteristic for this species.
• The diversity of fungal endophytes within a single root highlights the complex symbiotic relationships in orchids.