木兰科种子内种皮合点区形态及其系统学意义

在扫描电镜下系统研究了木兰科10属52种成熟种子内种皮合点区形态。该形态分为孔型和管型两大类。孔型为内种皮合点区具一小穿孔。木莲属Manglietia、香木兰属Aromadendron、盖裂木属Talauma(8种)、南洋含笑属Elmerrillia和鹅掌楸属Liriodendron具此类型。管型由内种皮合点区向下凹陷形成的小窝和由窝底向外伸出的小管组成。华盖木属Manglietiastrum、盖裂木属Talauma(3种)、长蕊木兰属Alcimandra、含笑属Michelia、合果木属Paramichelia和观光木属Tsoongiodendron具此类型。在木兰属部分种中还观察到两种形态之间的过渡类型。上述形态特征在属内稳定并为木兰科植物所特有，而且明显表现出原始类群的合点区形态大多为孔型，进化类群的合点区形态大多为管型的特点。

Chalazal region morphology on the endotesta of Magnoliaceous seeds and its systematic significance

The chalazal region on the endotesta of 52 species from ten genera in the Magnoliaceae was observed under scanning electron microscopy, and is found to be of two types in morphology: the pore type and the tube type. The former is characterized by having a simple pore, and was observed in Manglietia, Aromadendron, Talauma (eight species), Elmerrillia , and Liriodendron . The later is characterized by having a more complex structure consisting of a central hollow tube contained within a hole. This type was observed in Manglietiastrum, Talauma (three species), Alcimandra, Michelia, Paramichelia , and Tsoongiodendron . Transitional types between these two types were observed in some species of Magnolia . Such chalazal morphology is stable within genera and has been found only in the Magnoliaceae. It is noteworthy that the pore type is mainly found in the relatively primitive groups, while the tube type mainly in the relatively advanced ones of the Magnoliaceae.