Influence of activated charcoal on seed germination and seedling development by the asymbiotic method in Zygostates grandiflora (Lindl.) Mansf. (Orchidaceae)

The aim of this study is to examine the influence of activated charcoal on the seed germinating ability and seedling development of Zygostates grandiflora (Lindl.) Mansf. in in vitro culture. The seeds were obtained from a sterilised orchid capsule. They were sown on a Murashige and Skoog medium + indoleacetic acid (1.5 mg dm^-3) and benzylaminopurine (2.0 mg dm^-3) without the addition of activated charcoal and on a medium that contained 1.0 and 3.0 g dm^-3 activated charcoal, respectively, for 18 months. Initial differences in seed germination were observed after nine months since the beginning of the in vitro culture. The addition of activated charcoal had a positive influence on protocorm size and development. The results of this research were confirmed after 12 and 18 months of in vitro culture, where an intensive development of leaf and aerial roots occurred on a medium that contained the highest concentration of activated charcoal, i.e. 3.0 g dm^-3 as a supplement. The statistical analysis showed that the asymbiotic method of orchid propagation in in vitro culture could be used for Z. grandiflora, and that the addition of activated charcoal into the medium improved this method.