Orchid seeds of sixteen Brazilian Southern species were stored at 5ºC up to 42 months, when the viability was tested by the tetrazolium or germination performance. There was loss of viability when storage was extended. For one year, the viability of the majority of the seeds stored at 5ºC in a dessecator with ± 6% of water content was preserved near to 100%, except for Cattleya labiada which lost around 50% of its seeds' viability. Cattleya intermedia, Encyclia pigmaea, E. odorantissima, Grobya sp., Oncidium flexuosum, O. pumilum and one natural hybrid of Laeliocattleya maintained seed viability of over 90% to 24 months at 5ºC. Cattleya intermedia seeds were stored in polipropylene tubes at 5ºC or -18ºC and either 25ºC in a dessecator or in open flasks under laboratory environmental conditions. Most the seeds of this species died under laboratory conditions in one year. Storage at 5ºC or in a freezer (-18ºC) were the best conditions to maintain the orchid seed viability. With this same species the seeds were stored at -18ºC for 24 weeks, and the viability tested weekly.. The seeds were transferred directly from this temperature to 25ºC or indirectly, for one hour at 5ºC, and then to the environmental temperature in the laboratory (25ºC). The indirect transfer preserved viability more efficiently.
conservation; tetrazolium; germination; viability
