香蕉茎尖滴冻法保存中细胞的超微结构变化

 应用透射电镜研究了香蕉茎尖滴冻法超低温保存中细胞超微结构的变化规律。结果表明: 装载后, 细胞液泡化程度降低, 出现质壁分离。脱水处理使质壁分离程度加重, 原生质体浓缩, 一部分细胞的细胞壁、膜系统发生了不可逆的损伤; 也有小部分位于分生组织区域的细胞结构虽然发生了变化, 但程度不深, 在恢复培养时会自动修复, 并再生出植株。细胞严重伤害主要发生在脱水处理过程中, 冷冻环节基本上不产生新的损伤。讨论了上述变化的可能机制。

Ultrastructural Changes Associated with Droplet Vitrification Cryopreservation of Banana Shoot-tip

Ultrastructure of banana shoot-tip cells during droplet vitrification cryopreservation was observed by using the transmission electron microscopy (TEM). The results showed that loading decreased the degree of vacuolation and caused plasmolysis. The extent of plasmolysis became more severe and protoplast was condensed after dehydrating treatment. Meanwhile, cell walls, cell membranes and nucleus envelopes of some cells were lethally injured. Although there were some changes in the structure of many other cells, the damage was reversible, which might be rehabilitated automatically during recovery culture and regenerating plantlets could be obtained. Cells were mainly damaged during the dehydrating process, and no significant alterations occurred subsequently in the cooling step. The possible mechanisms for those results were discussed.