THE CONTRIBUTION OF SEM ANALYSIS IN EX SITU CONSERVATION PROJECTS CONCERNING PLANT BIODIVERSITY: STUDYING THE ORCHID-FUNGI RELATIONSHIP IN A IN VITRO SYSTEM

Orchidaceae is a large family of flowering plants that comprises many species, about 26.000, growing in a great diversity of environments and ecosystems. They establish mycorrhizal symbiosis in which diverse soil fungi lie in contact with orchid roots and colonize them. Fungal hyphae form consistent and peculiar structures inside root cells - fungal coils called pelotons - and exchange nutrients with their host. Nowadays, orchids are subject to a variety of threats in their natural habitat, but the projects aimed to conserve orchids biodiversity should take account of the highly specific relationship of orchid species with fungi. The objective of this study was to test an in vitro mycorrhizal system using plantlets of terrestrial orchids and strains of fungi isolated from orchid roots to improve plant acclimation.