两种海洋饵料硅藻的超低温保存

Cryopreservation of Two Marine Diatoms for Mariculture

用两步冷冻法对牟氏角剌藻和新月菱形藻进行了超低温保存，研究了影响存活率的内外因素．结果表明，对这两种藻分别选用１０％ 和１５％ ＤＭＳＯ为抗冻保护剂，预冻至－ ４０℃并保持３０ ｍ ｉｎ 后投入液氮，样品化冻后分别在室温及０℃采用较慢的稀释速率去除ＤＭＳＯ时可获得较高的存活率．此外，处于静止期或经过低温驯化的藻细胞也表现出较大的抗冻性．通过优化内外条件，两种藻的存活率分别达到９１．５％ 和６３．１％ ．

Chaetoceros muelleri and Nitzschia closterium are preserved in liquid nitrogen by a two step cooling method.The effects of intrinsic and extrinsic factors on the recovery are studied.It is found that the two diatoms could attain high survival rates when 10% and 15% DMSO are used respectively as cryoprotectants,the prefreezing temperature and time are -40℃ and 30 minutes respectively,and the slow dilution method is used to remove DMSO from the thawed samples at room temperature or 0℃ respectively.In addition,the algae in early stationary growth phase or undergoing cold acclimation show high tolerance to freezing.The viability of C. muelleri and N. closterium are 95.5% and 63.1% respectively under the suitable conditions of cryopreservation.