RESUMEN
Most plants that inhabit ant-gardens (AGs) are cultivated by the ants. Some orchids occur in AGs; however, it is not known whether their seeds are dispersed by AG ants because most orchid seeds are tiny and dispersed by wind. We performed in situ seed removal experiments, in which we simultaneously provided Azteca gnava ants with seeds of three AG orchid species and three other AG epiphyte species (Bromeliaceae, Cactaceae and Gesneriaceae), as well as the non-AG orchid Catasetum integerrimum. The seeds most removed were those of the bromeliad Aechmea tillandsioides and the gesneriad Codonanthe uleana, while seeds of AG orchids Coryanthes picturata, Epidendrum flexuosum and Epidendrum pachyrachis were less removed. The non-AG orchid was not removed. Removal values were positively correlated with the frequency of the AG epiphytes in the AGs, and seeds of AG orchids were larger than those of non-AG orchids, which should favour myrmecochory. Our data show that Azt. gnava ants discriminate and preferentially remove seeds of the AG epiphytes. We report for the first time the removal of AG orchid seeds by AG ants in Neotropical AGs.
Asunto(s)
Hormigas/fisiología , Orchidaceae , Dispersión de Semillas , Semillas , Animales , Bromeliaceae , Cactaceae , Jardines , Orchidaceae/fisiología , SimbiosisRESUMEN
BACKGROUND: Populations of Brassavola nodosa have been severely affected by habitat destruction and illegal collecting, and as with the majority of orchid species, it is critical to take action to guarantee their continued survival. OBJECTIVE: The present study aimed to establish protocols for the long-term conservation of protocorms of species. MATERIALS AND METHODS: Four different cryogenic techniques were compared: encapsulation-dehydration (ED), encapsulation-vitrification (EV), encapsulation-dehydration-vitrification (EDV) and vitrification. RESULTS: Preculture of protocorms with ABA was a critical factor in obtaining high percentages of regrowth. With vitrification, 100% regrowth was achieved in five treatments, mainly when protocorms were dehydrated with PVS2 for 120 min. 100% regrowth was also obtained with EDV, where the protocorms were precultured with ABA 5 mg/l for 3 days and incubated with PVS2 for 60 min. With the ED, regrowth of 72% was achieved with the preculture of protocorms with ABA 5 mg/l for the three times of incubation used (3, 6 and 9 days). In the case of EV, 92% regrowth, was recorded when protocorms were precultured for 9 days with ABA 3 mg/l and incubated with PVS2 for 90 min. CONCLUSION: Although regrowth of protocorms was obtained with all the techniques used, the vitrification technique is preferred since it requires less labour and is less costly.