In vitro culture of Osmunda regalis fern

The purpose of this study was to assess the behaviour of the fern Osmunda r egalis in ill vitro culture, to identify the most suitable conditions for p ossible micropropagation. Starting material was constituted by sports harve sted from a mature plant. Spores, germinated on gelled Hoagland and Amen gr owth medium, produced normal gametophytes and sporophytes. Sporophytes cult ivated both on MS and Hoagland and Arnon growth media consistently were sus ceptible to tissue vitrification, even when different cytokinins were used. On hormone-free growth medium, sporophytes looked normal and underwent con siderable growth but secondary meristems were produced only rarely. These s porophytes differentiated numerous sporangia containing spores capable of h igh percentage germination on the same growth medium. Gametophytes obtained from these spores produced sporophytes which were then successfully acclim ated.