| Summary: | 碩士 === 中興大學 === 生命科學系所 === 95 === Strawberry (Fragaria x ananassa Duch.) is one kind of temperate plants; therefore, it could be cryopreserved after preculture with cold acclimation. In this study, it is expected that the survival rates of two cultivars of strawberry cv. ''TY-1'' and ''TY-3'', could be maximized through the process of cold acclimation for 7 to 60 days and vitrificated cryopreservation. The results shows that the survival rates of these two kinds of strawberry were obviously promoted after cold acclimation for 30 days and cryopreservation. At first, the survival rate of these two cultivars without preculture was only 80%. However, the highest sur-vival rate of ''TY-1'' became 97% after the shoot tips were cryopreserved following loaded with loading solution (LS) (20 minutes), dehydrated with plant vitrification solution 2 (PVS2) (150 minutes). As for TY-3, the highest survival rate of TY-3 shoot tips was 96% after the procedure of LS (20 minutes), PVS2 (240-270 minutes) and cryopreservation. In addition, after a 30-day preculture on MS medium with 0.2 M sucrose, the TY-3 shoot tips were loaded for 60 minutes and then dehydrated for 240 minutes. After these treatments and cryopreservation, the survival rate of TY-3 shoot tips was 87%.
Moreover, during the process of preculture, there had been some decrease in the relative water content, water potential, and osmotic potential of the shoot tips, but there was an increase in the amount of soluble sugar content within apex tissue. All of the content of simple sugar, fructose, glucose and sucrose changed. Among which, sucrose was accumulated in shoot tips.As a result, the water status, osmore-gulation and enhance the strawberry shoot tips to adapt to the pretreatment of cryopreservation protocols and then being directly plugged into LN for cryopreservation. The morphology of the rewarmed shoot tips are the same with the normal ones . This outcome means that the regrowth of cryopreserved strawberry shoot tips were not variable after the protocols.
In conclusion, the protocol established in this study could be adapted to the cryopreservaion of two cultivars strawberry TY-1 and TY-3 by vitrifyication.
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