• Immature P halaenopsis seeds cannot tolerate drying and germinate poorly. • Incubation of excised immature seeds without free water increased germination. • Drying excised seeds slowly induced desiccation tolerance. • Excision of seeds induced two LEA protein genes regardless of drying. • Some LEA proteins may increase germinability. Long-term storage of many commercially valuable orchid seeds is uniquely challenging because they can only be germinated in aseptic culture, a practice requiring that fruits be prematurely excised before they dehisce to facilitate sterilization. The seeds from these fruits cannot tolerate the desiccation required for long-term storage, resulting in potential loss of valuable germplasm. Our aim is to develop methods to increase germinability and desiccation tolerance in immature orchid seeds to prepare them for long-term storage and to explore underlying biochemical factors. We assessed germinability, desiccation tolerance and expression of two typical L ate E mbryogenesis A bundant ( LEA) genes in Phalaenopsis amabilis, P. aphrodite and their hybrid seeds as a function of moisture content both during natural development and during experimental treatments of excised immature seeds. Germinability increased whenever excised seeds were incubated in the absence of free water at moisture contents high enough to permit protein synthesis, a treatment which resulted in the rapid (within 24 h) upregulation of two typical LEA genes. Whereas incubating excised seeds without free water at high moisture contents for 4 days improved germination and induced LEA genes, only drying of excised seeds over the course of 4 days induced tolerance to eventual moisture contents less than 10% moisture. In conclusion, our results suggest that the germination of seeds from orchid capsules excised prior to dehiscence (as for the green pod method) is improved by maintaining them for several days following excision at high relative humidity in the absence of free water. Such seeds can also be induced to tolerate desiccation - and thus potentially long term dry storage - by slowly drying them over the course of several days. Our results also support the hypothesis that some of the typical LEA proteins improve germinability but are alone insufficient for the development of desiccation tolerance.