In vitro regeneration systems of platycerium

Abstract

The staghorn fern genus, Platycerium, is an epiphytic genus, consisting of 15-18 species cultivated worldwide because of their unique appearance. Its economic value is great, since it stands out among ferns as one of the most commonly grown ornamental ferns. In vitro studies of some Platycerium species have revealed its great morphogenetic potential. Direct adventitious bud development was obtained on excised juvenile leaves without any growth regulators, what makes the excised-leaf culture system of Platycerium ideal for studying patterns of morphogenesis. Regeneration was also obtained on fragments of juvenile leaves, excised bud scales, and cell suspension culture. Apospory, the formation of gametophytes from sporophytic tissue in the absence of meiosis or sporulation, was also observed in Platycerium, and a simple, reproducible system for its induction is proposed. In this review, regeneration systems of Platycerium using in vitro techniques are summarized and compared to those among other fern species. The influence of initial explants, culture media, plant growth regulators, wounding, etc., on morphogenesis, including apospory and apogamy, is presented. Different regeneration systems are discussed with respect to their applicability to mass propagation. Some similarities in regeneration patterns between Platycerium and seed plants are also emphasized.