Our In Vitro Collection is used primarily to support Kew’s research in conservation and restoration. Orchids require mycorrhizal fungi for successful seed germination in the wild and this can be replicated under in vitro conditions. Until recently, it was difficult to culture, identify and use mycorrhizal fungi for seed germination of orchids. With advances in methods developed at Kew, symbiotic seed germination – where seedlings are grown with compatible mycorrhizal symbionts – is gaining momentum. As plants and fungi are stored at optimum growing conditions in vitro they can be used at any time of the year to support research and conservation programmes.
The current collection mainly contains specimens that support Kew’s programmes in the UK and Madagascar. The focus is on threatened orchid species and the collection contains representatives of epiphytic, lithophytic and terrestrial life forms. For the UK, this includes orchids that are close to extinction, such as Cypripedium calceolus and Dactylorhiza incarnata subsp. ochroleuca. For Madagascar, major genera such as Angraecum, Aerangis, Bulbophyllum and Cynorkis, which have high levels of endemism, feature highly in the collection. The mycorrhizal and non-mycorrhizal fungi in the collection are predominantly from Basidiomycota and Ascomycota.
The use of the In Vitro Collection at Kew is currently focused on the need to obtain a better understanding of symbiotic relationships in threatened UK species and on the benefits of mycorrhizal fungi in priority species for conservation in Madagascar.
Threatened orchids, particularly those that are on the brink of extinction, are priorities for new additions to the In Vitro Collection – from the UK and worldwide. Terrestrial orchids represent a third of all orchids, yet they constitute half of the orchids facing extinction. They are therefore a particularly vulnerable group and are prioritised for in vitro growth using symbiotic systems. The mycorrhizal fungal partners are either from the plants themselves or closely related taxa from the wild.
The benefits to plant growth and survival conferred by mycorrhizal and non-mycorrhizal fungi alike is an interesting area of science. Habitat-adapted endophytic fungi from crop wild relatives and other wild plants are also being added to the collection regularly for research into potential applications for improving crops and contributing to food security.