摘要
Ultrastructural changes in the sieve element and dense cells of nectariferous tissue during the development of floral nectary in Arabidopsis thaliana L. were investigated with transmission electron microscopy. Samples were prepared with high pressure freezing and freeze substitution techniques. The ultrastructure of dense cell was similar to that of sieve element at its early developmental stage. With the concurrent agglutination of chromatin in the nucleus, the abnormal location of organelles and the high density of cytoplasm, the ultrastructural characteristics in die dense cells of the nectariferous tissue and in the sieve element are matched with those of the programmed cell death in animal and plant reported in recent years. The disorganization of nucleus and most organelles in the differentiation of sieve elements and dense cells is closely associated with the transportation and modification of pre-nectar and the transference of nectar. This suggests that the cytological changes in sieve element and nectariferous tissue are closely associated with the nectary functional activities.
应用高压冷冻和低温替代技术 ,对拟南芥 (ArabidopsisthalianaL .)花蜜腺发育过程中细胞的超微结构变化进行了研究。蜜腺组织中深色细胞的超微结构与筛分子早期分化的超微结构十分相似 :细胞核中染色质逐渐出现凝集并且边缘化 ;细胞器分布异常 ;细胞质浓稠。这些超微结构特征与近年来报道的动植物细胞程序性死亡的超微结构相似。在筛分子和深色细胞分化中 ,细胞核及一些细胞器的逐渐解体与原蜜汁的运输、加工和蜜汁的分泌有直接联系。这反映了蜜腺发育过程中筛分子和蜜腺组织的细胞学变化是与蜜腺的生长。
基金
国家铁道部科学基金 (B98<18>)~~
