In vitro asymbiotic growth of Mediterranean terrestrial orchids from immature seeds.

In vitro germination of immature orchid seeds was carried out on two different culture media, with unlike nitrogen sources. BM1 culture medium, which makes available nitrogen in organic form, proved to be effective to promote both germination and further growth stages in many of the orchid species tested. Germination times were found to be variable within the species and likewise the time required for the plantlets' full growth. As well on KC mediu, which supply inorganic nitrogen, the germination occurred, but lower germination percentages were obtained compared to BM1. On KC only Serapias vomeracea subsp. laxiflora reached the plantlet stage, while all the other species remained at protocorm stage.