采用单因子比较和均匀设计法，研究凹叶厚朴（Magnolia biloba（RehdetWils）Cheng）愈伤组织超低温（－196℃）保存的影响因素。结果表明：超低温保存的适宜材料是4周龄的愈伤组织。经4～6℃低温下预培养12天的愈伤组织抗冻能力最强。较好的冷冻保护剂是12．5％DMSO＋5％Suc＋0．25％LH。较佳的冷冻程序是以0．5℃／min的降温速度从0℃降到－30℃，停留1h，然后浸入液氮中贮存。30℃水浴中化冻与自来水流水（18．5±1℃）冲洗化冻效果一样良好。化冻后的愈伤组织在黑暗中培养生长较好，存活率高。

The suitable factors in cryopreservation ( - 196℃) of the calli of Magnolia biloba  (Rehd et Wils) Cheng were studied by monofactorial and uniform. design. The experiments showed that four-weeked calli were the best material for cryopreservation. Calli treated for 12 days at 4 - 6℃were the best cryotolerant. The best cryoprective was the mixture of 12.5 % DMSO, 5 % Suc and 0.25 % LH. The best freezing procedure was to reduce the temperature from O℃ to - 32℃ at a stable speed by lowerring 0.5℃ each minute , leave the calli at - 3 2℃ for 1 h , then drop them in liquid nitrogen
( - 196℃ ) to be preserved. Warm-water bath at 30℃ was as good as flowing-water wash at 18.5± 1℃for melting the frozen material. Unfrozen calli were then cultured in darkness and grew well with a high survival rate.