猕猴桃茎尖超低温保存过程中超微结构观察

应用透射电镜观察了猕猴桃组培苗茎尖细胞在玻璃化法超低温保存过程中的超微结构变化.研究发现:在预培养、PVS2脱水处理过程中,茎尖细胞内液泡逐渐变多、变小,质壁分离愈加显著,表明细胞的抗冻力增强;在随后的冷冻和解冻过程中,部分细胞的质壁分离更加严重,细胞壁与细胞膜之间出现液腔,细胞器变得模糊,有些细胞的细胞膜、甚至细胞壁撕裂,细胞腔内留下破碎的细胞膜和细胞残片,细胞结构破坏严重,这可能是导致材料在恢复培养中死亡的原因之一;部分细胞经过7d的恢复培养后,细胞器清晰,细胞膜完好并紧贴细胞壁,细胞中央出现较大的液胞,具有与对照相似的结构特征,最终存活下来并能够再生植株.

Ultrastructure of in vitro Stem Apex of Kivi in Cryopreservation

Transmission electron microscopy was adopted to examine the ultrastructure of in vitro stem apexes of kivi through vitrification cryopreservation.It was found that the cells of the stem apexes increased their vacuole number and decreased their vacuole sizes and suffered significantly increased plasmolysis in their pre-culture and PVS_2 dehydration,showing an enhanced anti-frost capacity;during the following freezing and thawing process,some of the cells suffered much more severe plasmolysis and showed sap cavities between their cell wall and cell membrane,blurred organelles,and some of them showed lacerative cell membrane and even tearing cell wall with cell membrane and cellular fragments in their cavities,which was probably one of mortality reasons in recovery culture;after seven-day recovery culture of the cells,some of the cells showed clear-cut organelles and complete cell membrane closing up to the cell wall,and larger vacuoles in their central parts,and similar structural features to the control cells,and finally survived and regenerated the plantlets.