木立芦荟叶内芦荟素的超微细胞化学研究

使用醋酸铅溶液对木立芦荟叶的药用成分芦荟素进行细胞化学定位,在透射电镜下探讨芦荟素产生、转运和贮藏的过程。结果表明:芦荟素由同化薄壁组织产生,质体的类囊体为其合成部位。通过质体膜形成的小泡转移到周围的内质网,以后内质网小泡与质膜融合:或质体小泡直接与质膜融合。通过胞吐作用将芦荟素释放到质膜外,经质外体途径到达维管束的鞘细胞。在鞘细胞中, 芦荟素经内质网小泡转移至内切向壁,由胞间连丝运输到芦荟素细胞的细胞质,最终贮藏在芦荟素细胞的液泡中。

ULTRACYTOCHEMICAL STUDIES OF ALOIN IN ALOE ARBORESCENS LEAVES

Lead acetate precipitation method was used for ultracytochemical localization of aloin. The processes of aloin production, transport and storage were studied by transmission electron microscope. Results showed that aloin was produced in the plastids of the assimilating tissue. The aloin was transported through the plastid membrane to the surrounding endoplasmic reticulum and enveloped in the vesicles by the endoplasmic reticulum elements, the vesicles approached and later fused with the plasmalemma. Some vesicles of the plastid membrane directly fused with the plasmalemma. The vesicles released their contents into the apoplast through exocytosis, and finally reached the vascular bundle sheath by apoplastic translocation. Aloin was transported to the internal tangential wall of vascular bundle sheath cell through endoplasmic reticulum vesicles, and reached the cytoplasm of aloin cell by means of plasmodesmata. Finally, aloin was stored in the vacuoles of aloin cell.