Germination of Helminthostachys Spores

Abstract

For nearly a century the spores of the Ophioglossaceae have been sown, but few investigators have succeeded in germinating them (Boullard, 1963). Campbell (1895, 1907) was the most successful in germinating spores of the Ophioglossaceae on soil. He reported the early stages of germination of spores of Botrychium virginianum (Campbell, 1895) and of three species of Ophioglossum (Campbell, 1907). An earlier report on spore germination in B. ternatum by du Buysson (1889) remains in question (Whittier, 1981) because the gametophytes that developed had essentially the same morphology as gametophytes of leptosporangiate ferns. More recently, spores of Botrychium and Ophioglossum have been germinated in axenic culture (Whittier, 1972, 1981; Gifford & Brandon, 1978). These spores germinated in the dark on nutrient media containing minerals and sugar. In some cases, the spores took 3-4 months to germinate under these conditions (Whittier, 1981). The mature gametophyte of Helminthostachys, the third genus of the Ophioglossaceae, has been described from nature (Lang, 1902; Nozu, 1961; Pant et al., 1984). It usually has a long, thick, cylindrical axis with numerous short lobes at its base. The lobes have apical meristems and appear to be short branches (Pant et al., 1984). The basal region of the gametophyte contains the mycorrhizal fungus and the cylindrical portion bears the gametangia. Spore germination and early stages of gametophyte development are unreported for Helminthostachys. Since germination and gametophyte development in Botrychium and Ophioglossum have been studied with the techniques of axenic culture, the aim of this study was to use these techniques to determine the conditions that promote germination and early gametophyte development in Helminthostachys.