This study is the first approach to in vitro asymbiotic germination of two species of Sicilian threatened terrestrial orchids, Anacamptis longicornu and Ophrys panormitana. Seeds were collected in the wild and cultured in two different media-Orchimax medium (OM) and Murashige and Skoog (MS)-and exposed to different photoperiods and temperatures to evaluate the best conditions for the specific stages of development. The germination of A. longicornu was very high on OM (95.5%) and lower on MS medium (21.4%), whereas O. panormitana germinated only on OM medium, with significantly lower percentages (12.0%), compared with A. longicornu. This difference is caused by variation in quality and quantity of nutrients used, primarily by nitrogen source. The results show that temperature and photoperiod widely affect seed germination and development. Although further investigations on asymbiotic and symbiotic germination are needed for the improvement of conservation of Mediterranean terrestrial orchids, our results contribute to the conservation of this group of plants.
Keywords: Mediterranean terrestrial orchids; acclimatization; embryonic developmental stages; endangered species; photoperiod.