Ploidy analysis of Cymbidium, Phalaenopsis, Dendrobium and Paphiopedillum (Orchidaceae), and Spathiphyllum and Syngonium (Araceae)

Endopolyploidy is typical and wide-spread in the Orchidaceae. In this study, an attempt was made to quantify the ploidy of mature callus and mature protocorm-like bodies (PLBs) of nine hybrid Cymbidium cultivars cultured in vitro, as well as different flower parts (dorsal sepal, petal, lateral sepal, labellum, pedicel, column, anther cap, stigmatic surface) and youngest leaf of Phalaenopsis and Paphiopedillum and in leaf tissues of in vitro Spathiphyllum and Syngonium plants. Polyploidy was detected in in vitro cultures, primarily in PLBs, ant to a limited extent in floral tissue: 8C was detected in the pedicel and column, but never exceeding 3%. This study expands on the number and breadth of cases of endopolyploidy in orchids, with novel information about Paphiopedillum. These findings may be useful for better understanding developmental processes in vitro or in planta, and may be the first step to revealing evolutionary or adaptive mechanisms of survival of orchids in response to environmental or abiotic stresses.