In vitro desiccation tolerance of the epiphytic Ghost Orchid, Dendrophylax lindenii (Lindl.)Benth x. Rolfe

The Ghost Orchid, Dendrophylax lindenii (Lindl.)Benth x. Rolfe, is a rare and endangered epiphytic orchid native to south Florida and Cuba. The orchid is considered difficult to propagate under greenhouse conditions, requiring high humidity and low air movement. In contrast, the orchid's native habitat seasonally dries out with decreased precipitation and humidity. This suggests some level of desiccation tolerance. Ghost Orchid plants were assessed for potential desiccation tolerance and ability to recover from desiccation stress under in vitro conditions. In vitro-derived plants were placed into sterile baby food jars and transferred to chambers maintained at 10 percent relative humidity, which is extremely low compared to relative humidity levels (40-100 percent ) recorded under natural field conditions. Plants were removed every week for 4 wk and recovered on P723 medium supplemented with banana powder for 4 wk. Data were collected at the initiation of the experiment, after the desiccation periods, and after 4 wk in vitro recovery. Ghost Orchid plants demonstrated extremely high desiccation tolerance. Even after 4 wk desiccation, plant survival was observed at 79.2 percent after recovery. Desiccated plants exhibited significant decreases in tissue water potential (??18.44 MPa), fresh weight (65.5 percent loss), and water content (14.2 percent ); however, high plant survival was still observed under these conditions similar to poikilohydric plants. Overall, the Ghost Orchid demonstrated high desiccation tolerance, which should be considered for future greenhouse culture and for its application in the direct field establishment of in vitro-derived plants without greenhouse acclimatization.