五味子科比较木材解剖及其系统学意义

在光学显微镜和扫描电镜下观察了南五味子属Kadsura 7种21个样品和五昧子属Schisandra 8种14个样品的木材解剖特征，结果表明次生木质部的导管分子类型、导管一射线间纹孔的排列方式、射线类型、射线细胞形状等性状在科的水平上很稳定，这些共同特征都支持五味子科Schisandraceae是比较自然的类群。在五昧子科中发现木材导管单生、具梯状穿孔板、导管壁具梯形排列的纹孔以及木射线异型等原始性状，支持五味子科在被子植物中的原始地位。此外，该科木材还具有单穿孔板导管、导管次生壁具螺纹加厚、具分隔纤维等较为特化的性状状态，这种性状进化水平的异等级现象，使五味子科表现出不同进化水平性状的镶嵌组合。根据木材解剖性状对五味子科进行UPGMA聚类分析，所得结果显示南五昧子属和五味子属在木材解剖特征方面有一定的交叉和重叠，这与分子系统学的结论一致，表明这两个属关系密切，可能起源于共同的祖先。通过比较五昧子科与八角科Illiciaceae的木材解剖特征，进一步证明两个科的亲缘关系很近，不支持将五味子科从八角目Illiciales中独立出来成立五味子目Schisandrales的观点。

Comparative wood anatomy of Schisandraceae and its systematic significance

The wood anatomy of 21 collections of 7 species within Kadsura Kaempf. ex Juss. and 14 collections of 8 species of Schisandra Michx., representing a large proportion of two genera in Schisandraceae, was investigated using light microscopy and scanning electron microscopy. Several features in the secondary xylem, such as types of vessel elements, arrangement of vessel-ray pitting, types of ray and shape of the body ray cells, show consistent characteristics at the family level, which support the view that Schisandraceae represents a monophyletic group. The antiquity of Schisandraceae is supported by the presence of single vessel, scalariform perforation plates with many bars, scalariform vessel pitting and heterogeneous rays. A few apomorphic character states, such as simple perforation plates, helical thickenings in secondary walls of vessels and septate fibers, can be found in Schisandraceae, which make this family a mosaic with both plesiomorphic and apomorphic character states. A UPGMA analysis shows that species of Kadsura and Schisandra overlap in a dendrogram, which is congruent with the results from molecular data and indicates that the two genera are closely related, perhaps originating from the same ancestor. The wood anatomy evidence also confirms a close relationship between Schisandraceae and Illiciaceae, and does not support separation of Schisandraceae from Illiciales as Schisandrales.