Advancements in the Symbiotic Culture of Native Orchid Species
Growing native orchids from seed is a challenging and long-term task with many research opportunities. Symbiotic germination, where orchid seeds are inoculated onto an actively growing culture of known orchid mycorrhizal fungi (OMF), is the primary way to ensure that laboratory propagated orchid seedlings establish a fungal relationship. Despite reports on increased and faster germination in symbiotic orchid seed germination studies, few studies report on development beyond the seedling stage to seedlings large enough to survive ex vitro conditions. Even fewer studies have experimented with other techniques and timings of inoculating orchid seedlings with OMF. To this end, we are focusing our research efforts on defining new techniques for growing OMF fungi and evaluating different timing intervals of OMF inoculation of asymbiotically produced seedlings, in order to identify an approach that has utility for improving the success of establishing and growing native orchids. Initial results using OMF grown on cellulose based sorba rods and on potato broth indicate the orchid seedling survival and growth are increased when inoculated with OMF isolated from roots of adult orchid plants for Goodyera tesselata, Platanthera blephariglottis, and P. ciliaris. Our results also show that choice of substrate and environmental parameters play a significant role in the establishment of seedlings, and that there is room for further experimentation combining these factors with OMF inoculation. This is an expanding area of conservation research at Longwood Gardens with the goal of facilitating large scale propagation and production of native orchid seedlings to support ex situ collections development and restoration efforts.