Asymbiotic germination, seedling establishment and fungal uptake of Pterostylis montana and P. paludosa, two orchid species endemic to New Zealand

Abstract

ABSTRACT Asymbiotic germination of orchid seeds has been successful for many species, and this could be an important method to generate seedlings to restore threatened populations. However, successful reintroduction of orchids into wild habitats depends on establishment of mycorrhizal symbioses. This communication reports on asymbiotic methods used to propagate two greenhood species endemic to New Zealand, Pterostylis montana (Not Threatened) and P. paludosa (At Risk – Declining). We furthermore investigated whether asymbiotically generated seedlings were colonised with orchid mycorrhizal fungi (OMF) when introduced to soil collected from natural forest areas where these species are not known to occur. We found that seedlings transferred to natural soil hosted at least seven different endophytic fungi, but no known OMF. We caution against the use of asymbiotically germinated seeds for reintroductions before getting a better understanding of the dynamics of mycorrhizal infections and their distribution in the soil.