四合木(Tetraena mongolica Maxim.)和霸王(Zygophyllum xanthoxylum(Bunge)Maxim.)营养器官比较解剖

观察表明:四合木和霸王的叶都有一条主脉和一条从基部出发止于叶缘中部的大侧脉;二者都为环孔材。同时,二者都以发达的皮层纤维、叶肉棚栏组织发达、叶肉细胞壁皱褶等共同的方式适应干旱环境。四合木和霸王有许多明显的解剖学差异,以不同的方式适应干旱环境,表现出系统上的差异,如四合木初生根为四原型,而霸王及蒺藜科绝大部分类群的根为二原型;四合木次生木质部为同型单列射线,多生活纤维而少木薄壁细胞,而霸王为同型单列和同型多列两类射线,以后者为主,并且多木薄壁细胞而不见生活纤维;四合本叶表皮的角质膜薄。密度丁字毛,气孔极下陷,而霸王叶表皮角质膜厚,无表皮毛,气孔下陷较小;此外,四合木基本组织中富含簇品细胞,茎中具特殊的油细胞,而霸王中不存在。这些差异特征支持一些分类工作者把四合木属从霸王亚科分出,新成立四合木亚科(Tetranenoideae Maet S. Z. zhang)。

A Comparative Anatomy on the Vegetative Organs of Tetraena mongolica Maxim and Zygophyllum xanthoxylum (Bunge) Maxim

In present paper the vegetative organs of an endemic species-Tetraena monagolica Maxim. in the NetMon- gol dersert ,were observed and compared with a affinity-species-Zygophyllum xanthoxylum(Bunge)Maxim. The results show that the leave of T. mongolica and Z. xanthoxylum have a main vein, and a large lateral vein from base to medium of margin. Both of the species have helical tracheary element in their xylem which rec- ognized as the characteristic of the Zygophyllaceae. Both of the species adapted with the xeric environment by the developed cortical fibre, palisade tisssue and thin-walled cells in mesophyll, But there are many botanical differences between T. mongolla and Z. xanthoxylum, and the differences showed that the species adapted xeric environment by the different ways. The primary root of T. mongolica is tetraarch, but of Z. xanthoxylum and most species of Zygophyllaceae are diarch. The secondary xylem of T. mongolica have homo- cellular uniseriate rays, more living fiores and less xylem parenchyma cells, but of Z. xanthoxylum have ho- mocellular uniseriate and homocellular multiseriate rays, the later of them is the main type. The secondary xylem of Z. xanthoxylum have more xylem parenchyma cells and no living fibre. The leave epidermis of T. mongolica have thin layer cutin, dense hairs and strong substomatal chambers, but of Z. xanthoxylum have thick layer cutin ,no hairs and light substomatal chambers. In the addition ,T. mongolica have abundant druse cells in its elementary tissue and special oil cells in its secondary stem, but Z. xanthoxylum have not these structure. We supported the idea of constiuting a new subfamily-Tatraenoideae Ma et S. Z. Zhang based on the botanical differences between T. mongolica and Z. xanthoxylum.