FUNCTIONAL SYNCARPY BY INTERCARPELLARY GROWTH OF POLLEN TUBES IN A PRIMITIVE APOCARPOUS ANGIOSPERM, ILLICIUM FLORIDANUM (ILLICIACEAE)'
FUNCTIONAL SYNCARPY BY INTERCARPELLARY GROWTH OF POLLEN TUBES IN A PRIMITIVE APOCARPOUS ANGIOSPERM, ILLICIUM FLORIDANUM (ILLICIACEAE)'
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DOI：
10.1002/j.1537-2197.1993.tb13780.x
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发表时间：
1993-02
影响因子：
3
通讯作者：
E. Williams;T. Sage;L. B. Thien
中科院分区：
文献类型：
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作者：
E. Williams;T. Sage;L. B. Thien
荧光显微镜和组织学研究表明，在八角属（八角科），一个原始的离心皮被子植物，功能性的合心皮是通过花粉管的心皮间生长。当花粉在心皮轮生的独立柱头冠上萌发后，管在心皮内倾斜向下向内向中轴生长，中轴被修饰为柱头状的顶端残体。“在顶端残体基部周围的有限浅区中，一些花粉管在心皮的未融合边缘之间生长出来，并环绕着顶端残体的表面，从那里它们可以进入相邻的心皮。有些花粉萌发和花粉管生长也发生在顶端残体上。顶端残体及其相关的未融合的心皮边缘作为一个extragynoecial compandum为花粉管在心皮之间的转移，因此，被认为是代表了一种机制，提高结实率。八角属的花粉管通道似乎是一个原始的表达线的进化发展，导致合心皮雌蕊，通过阶段可能举例说明某些成员的Trochodendraceae（较低的Hamamelididae）。
Fluorescence microscopy and histological studies have been used to show that in Illicium floridanum Ellis (Illiciaceae), a primitive apocarpous angiosperm, functional syncarpy is achieved by intercarpellary growth of pollen tubes. After pollen germinates on the separate stigmatic crests of the carpellary whorl, tubes grow within the carpels obliquely down and inward toward the central floral axis which is modified as a stigmalike "apical residuum." In a restricted shallow region around the base of the apical residuum, some pollen tubes grow out between the unfused margins of the carpels and circumferentially around the surface of the apical residuum from where they may enter neighboring carpels. Some pollen germination and tube growth also occur on the apical residuum itself. The apical residuum with its associated unfused carpel margins acts as an extragynoecial compitum for pollen tube transfer between carpels, and, as such, is believed to represent a mechanism for increasing the efficiency of seed set. The pollen tube pathway of Illicium appears to be a primitive expression of a line of evolutionary development leading to syncarpous gynoecia through stages possibly exemplified by certain members of the Trochodendraceae (lower Hamamelididae).