Abstract
Nymphaea capensis is an aquatic plant which produces recalcitrant seeds. Its’ seeds were desiccation intolerant and metabolically active. Cryopreservation is suggested because the conventional methods could not provide a stable storage environment for the seeds. Vitrification pretreatment was used to avoid the formation of ice crystals in cryopreservation. This study showed that cryopreserved seeds which progressed 12 h and 18 h of plant vitrification solution 3 (PVS3) treatments brought the highest germination rate (66.7%) among various pretreatment periods. The glass transition temperature (Tg) of 75% w/v sucrose + 25% w/v propylene glycol (PG) solution (-63.6℃) had the largest improvement among the alternative vitrification solutions compared to PVS3 (-90.7℃). Isoetes taiwanensis is a semiaquatic plant which is listed as a critically endangered species based on the criteria of IUCN. In contrast to the seeds of N. capensis, the plants of I. taiwanensis could tolerate air-dried for ca. one year in room temperature. Air-dried corms were retained 10% survival rate after 11 months storage under 4℃ and able to regrow new leaves and roots after rehydration. However, corms completely lost viability in cryopreservation even if various pretreatments were used.