中国芸香科植物叶分泌囊比较解剖学研究

COMPARATIVE ANATOMY OF SECRETORY CAVITIES IN LEAVES OF THE RUTACEAE IN CHINA

利用整体透明、石腊和薄切片方法对芸香科２２属，４０种和２变种植物叶分泌囊的形态结构和分布进行了比较研究。成熟分泌囊都由鞘细胞和一层上皮细胞围绕圆形腔隙构成，上皮细胞扁平，细胞壁薄、完整，故分泌囊属裂生方式发生。鞘细胞１～５层，不同种类的层数有变化，个别种缺乏。内层鞘细胞为扁平的薄壁细胞，外层的细胞壁较厚。分泌囊的形态结构、着生位置和分布密度等在不同属或不同种间存在一定差异。根据分泌囊在叶中的分布位置和形态结构特点，可将其划分为：叶缘齿缝分泌囊，叶肉分泌囊和两者混合型。叶肉分泌囊又可分海绵组织分泌囊和栅栏组织分泌囊。在此基础上对该科各类型分泌囊的形态演化关系以及各亚科或各属间的亲缘关系进行了探讨。

Comparative observations were made on the morphology and anatomy of secretory cavities in leaves of 22 genera, 40 species and two varieties by the whole mounting, paraffin and thin section method. A mature cavity consists of one layer of epithelial cells surrounding a large intercellular space and one to five layers of peripheral sheath cells. The epithelial cells were flattened, thin walled and integrated, which suggests that the cavities developed schizogenously. The sheath cells were also flattened. The cell walls of the outer layers had relative thickenings. The number of layers of the sheath cells varied with species. A few of species appeared to lack the sheath cells. The localization and structure of the cavities were correlated with taxa at generic and specific level. According to their structural features and arrangement in leaves, the secretory cavities can be grouped into four types as follows: the notch type (between the leaf teeth), the mesophyll type which is subdivided into spongy parenchyma subtype and palisade parenchyma subtype, and the mixed type (with both notch and mesophyll cavities). Based on these observations evolutionary trends concerning the morphology and anatomy of cavities and affinity among subfamilies or genera are discussed. It is suggested that the mixed type of cavities developed from the notch and mesophyll types.