(60(4):309-317)Effects of Drying Treatment and Cryopreservation on Seed Viability of Phalaenopsis amabilis and Phalaenopsis aphrodite

Phalaenopsis amabilis (L.) Blume及Phalaenopsis aphrodite Rchb. f.為白花原生種蝴蝶蘭，是極重要之育種材料。本研究測試乾燥處理與超低溫保存對該二原生種種子活力的影響，結果顯示Phal. amabilis無論有無經過超低溫處理，其種子活力率及發芽率皆隨乾燥處理日數之增加而降低。新鮮種子未經過乾燥處理而直接進行超低溫保存後仍有99.3%之發芽率，而乾燥處理1、4或7天之種子發芽率分別為96.7、87.0或72.0%。然而，Phal. aphrodite新鮮種子若未經過乾燥處理而直接進行超低溫保存，則種子完全失去活力，種子經播種4週後亦完全不生長。而種子經過1–7天之乾燥後再進行超低溫保存，種子之活力率雖然由87.0%降至77.0%、而發芽率由97.0%降至87.0%，但是仍有極高之活性。本研究顯示不同原生種蝴蝶蘭種子對超低溫保存所需之乾燥需求不同，對此二個原生種而言，乾燥處理1天後再進行超低溫保存，可保持與新鮮種子相同之活力。 Phalaenopsis amabilis (L.) Blume and Phalaenopsis aphrodite Rchb. f., are important native species of white flower Phalaenopsis used in the orchid breeding program. The objective of this study was to determine effects of seed-drying and cryopreservation on seed viability of these two native Phalaenopsis species. Results showed that viability and germination of Phal. amabilis seeds, with or without cryopreservation treatment, decreased with increased time of drying treatment. Germination rates of seeds of Phal. amabilis drying for 0, 1, 4 and 7 days and then treated by cryopreservation were 99.7, 96.7, 87.0 and 72.0%, respectively. In Phal. aphrodite, cryopreservation of fresh seeds without pre-treatment of seed drying resulted in complete loss of seed viability and germinability. However, when the seeds were dried for 1–7 days and then treated with cryopreservation, viability and germination of seeds of Phal. aphrodite remained high, 77.0% for viability and 87.0% for germination. These results indicate that the time required for seed drying treatment before cryopreservation varies between Phal. amabilis and Phal. aphrodite and that seeds drying for 1 day before cryopreservation can maintain the same viability as the fresh seeds without cryopreservation