矽膠乾燥法(silica gel desiccation)已成功應用於台灣白及(Bletilla formosana)種子超低溫保存(cryopreservation)，本研究持續探討經24 h乾燥的種子配合不同超低溫保存期間對台灣白及與白花蝴蝶蘭(Phalaenopsis aphrodite subsp. formosana)種子保存後活力之影響。經於液態氮(liquid nitrogen; LN)保存48 mo後，台灣白及種子仍能維持87.7%高發芽率，比新鮮種子更高；白花蝴蝶蘭種子於LN保存15 mo後，亦能維持100.0%高發芽率，且較新鮮種子發芽率(74.6%)顯著更高，後續小苗生長發育也正常。將乾燥法作為前處理，應用在紅花鶴頂蘭(Phaius tankervilleae)花粉、白花蝴蝶蘭、雅美萬代蘭(Vanda lamellata)及丹尼森萬代蘭(Vanda denisoniana)的種子超低溫保存。結果顯示，經過前處理再於LN保存之紅花鶴頂蘭花粉可維持高發芽率(81.0%)，在種子保存方面，經過24 h乾燥處理再進行超低溫保存24 h，保存後白花蝴蝶蘭、雅美萬代蘭、丹尼森種子發芽率分別為88.0%、100.0%及100.0%。其中，雅美萬代蘭種子對水分逆境具有耐性，能夠忍受乾燥且能於低溫下保存不會失去活力，符合正貯型種子的特質。因此，矽膠乾燥法同樣適用於紅花鶴頂蘭花粉、白花蝴蝶蘭、雅美萬代蘭及丹尼森萬代蘭種子，可作為超低溫保存之前處理。

Desiccation method has been successfully applied for the cryopreservation of Bletilla formosana seeds (Orchidaceae). This study investigated the effects of cryostorage duration on the viability of B. formosana and Phalaenopsis aphrodite subsp. formosana seeds after cryopreservation. After 24 h desiccation by silica gel and cryopreservation for 48 mo, B. formosana seeds still remained high germination percentage (87.7%) and higher than fresh seeds. Phal. aphrodite subsp. formosana seeds could retained significant higher germination percentage (100.0%) than fresh seed treatment (74.6%) after cryopreservation for 15 mo. The plantlet from cryostoraged seeds could grow and develop well. The germination percentage of dried and cryopreserved seed for 24 h was higher than that of fresh seeds after cryopreservation. Under scanning electron microscopy, it is clear that immersing seeds in liquid nitrogen (LN) induces breakage in the seed coat, then cracks in the seed coat provide channels that facilitate hydration and may increase germination. The technique could be applied for the pretreatment prior to cryopreservation of Phaius tankervilleae polllen, Phal. aphrodite subsp. formosana, Vanda lamellata and Vanda denisoniana seeds. The results showed that the germination percentage of freshly harvested pollen of P. tankervilleae was 81.4%, pollens directly placed in LN was low (25.4%) after thawing. However, the germination percentage increased to 81.0% for seeds dried with silica gel for 24 h prior to cryopreservation. In the case of seed preservation, the water content of V. lamellata fresh seeds was 34.6%, then decreased to 4.2% after desiccation for 24 h. The germination percentage of Phal. aphrodite subsp. formosana, V. lamellata and V. denisoniana fresh seeds were 77.5, 93.8 and 100.0%, respectively. The germination percentage of seeds that were directly placed in LN was low (0.0, 0.0 and 1.6%) after thawing, instead, the percentage increased to 88.0, 100.0 and 100.0% for seeds dried with silica gel for 24 h prior to cryopreservation for 24 h, respectively. These findings demonstrate that the seeds of V. lamellata exhibit a high tolerance toward desiccation and is suitable to be preserved at low temperature for long-term, and can be considered as an orthodox seed storage. Therefore, silica gel desiccation could be also applied for P. tankervilleae pollens, Phal. aphrodite subsp. formosana seeds, V. lamellata seeds and V. denisoniana seeds prior to cryopreservation.