关键词: 银杏, 根生垂乳, 分泌腔, 解剖结构, 组织化学

Abstract: This study took rooted chichies of Ginkgo biloba L. as experimental material，according to use the resin semi-thin section technique to observe the occurrence and developmental process of secretory cavities and use the histochemistry method to preliminarily study the basis secretion of secretory cavities. The results show that：The secretory cavities consists of two-three stratums of sheath cells and one stratum of secretory cells around a round or oval cavity. The average diameter of secretory cavities is 566.7 μm. The secretory cavities are developed from the schizolysigenous of original cell clusters which cells are small but with large nucleus and dense cytoplasm. The intercellular layer of central cells in original cell clusters swells，expands and finally forms intercellular space along with the secretory cavities developing. When the intercellular space expands to a certain extent，central cells of original cell clusters begin to dissolve. The secretory cavities gradually expands with central cells continually dissolve until central cells stop dissolving，then a mature secretory cavity forms. A large number of secretory cavities with different degree of developments are located in the cortex of tip and the meristem of adventitious bud in the tip of rooted chichi. The original cell clusters in rooted chichi have obvious osmiophilia，nucleoprotein is abundant while starch grain is a fat lot. During the central cells dissolving period，there are osmiophilic materials in all secretory cells and cavities with a mass of protein material and a spot of starch grain. After the secretory cavities mature，there is no protein and starch grain in cavities while secretory cells and sheath cells both have strong osmiophilia.

Key words: Ginkgo biloba, rooted chichi, secretory cavity, anatomy structure, histochemistry