洋葱根冠外缘细胞编程性死亡过程中的超微结构研究

摘要

洋葱根冠外缘细胞在发育过程中发生细胞编程性死亡。用透射电镜观察结果表明， 根冠中部细胞（Ⅰ）代谢活跃，中部两侧细胞（Ⅱ）逐渐粘液化同时表现出逐渐的液泡化过 程，边缘1～3层细胞（Ⅲ）则表现出类似动物细胞编程性死亡的典型超微结构特征，核染色 质凝聚在核膜边缘，胞质及细胞器表现出一种自噬作用，同时发现在动物细胞编程性死亡中 未报道的核突起现象。%The outmost layers of cells of the Allium sativum root caps involve in programmed cell death in their development process .The cells in the central pa rt of the root cap（Ⅰ）are characterized by high level of metabolic activity.T h e middle part cells （Ⅱ）between center and peripheral part are characterized b y the appearance of mucilage and vacuolization. The outmost cells (Ⅲ) exhibit condensation and shrinkage of chromatin of nucleus. Sometimes nucleus breaks int o small packets and autophagic vacuoles appear in cytoplasm. These characteristi cs are similar to classical characteristics in programmed cell death of animal c ells. Nuclear lobing has been found in the process of programmed cell death of p eripheral cells of the root cap, this nuclear lobing phenomenon has not been re ported in that of animal cells.