Morphological and tissue culture studies of platycerium coronarium, a rare ornamental fern species from Malaysia

The genus Platycerium consists of about 18 species, commonly found in tropical and subtropical forests. Among the different species, Platycerium coronarium, P. platylobium, P. ridleyi and P. wallichi are found in Peninsular Malaysia, and P. coronarium is considered the most attractive ornamentally. Platycerium coronarium is an epiphytic fern, bears a gigantic morphology and is native to tropical areas of South America, Africa, Southeast Asia, Australia and New Guinea. Platycerium coronarium nests on the upper branches of the tallest trees in the forest. Due to having a uniquely-shaped fronds, they are famous for ornamental purposes, where they can be found in gardens, especially in tropical regions. Detailed morphological studies of this species are lacking. In the present work, data are reported aiming at defining both the macro- and micro-morphological characteristics of intact and in vitro P. coronarium. Data from scanning electron microscopy (SEM) revealed similar ultrastructures of both types of leaves, i.e., the presence of multicellular trichomes on both the abaxial and adaxial surfaces. Sunken stomata were also detected on the abaxial surface of the leaves. In addition, tissue culture studies were done to obtain an efficient regeneration system as well as to serve as an approach for conservation. Successful regeneration of sporophytes from gametophyte explants were observed in MS medium supplemented with 1.0-1.5 mg/l GA(3) and 30 g/l sucrose, at pH 5.8 under 16 hours light and 8 hours dark