Greenhouse acclimatization methods for field establishment of in vitro–derived ghost orchid (Dendrophylax lindenii) plants

Abstract

The ghost orchid, Dendrophylax lindenii (Lindl.) Benth. ex Rolfe (Orchidaceae), easily acclimatizes in the greenhouse under a wide range of misting frequencies. The ghost orchid has previously been considered difficult to grow under greenhouse conditions, requiring low air movement and high relative humidity. Determining successful greenhouse conditions is important for the conservation of the ghost orchid in order to acclimatize in vitro–derived plants for field reintroduction. Furthermore, root attachment should be minimized during this acclimatization in an effort to reduce root damage when removing roots from the substrate during outplanting. In vitro–derived plants were transferred to the greenhouse using 2 substrate support systems that were placed under 3 mist frequencies (30 s of mist every 1, 2, or 3 h) for 28 d. Plants exhibited 100% survival and no difference in growth under the 3 mist frequencies. The 2 substrate support systems resulted in minimal root damage and were not significantly different. These results suggest that the greenhouse and substrate conditions utilized can be successfully applied to conservation programs, especially considering the orchid appears to be adaptable to a wide range of irrigation intervals. The high survival observed in the infrequent mist frequency may suggest desiccation tolerance.