摘要
本文对鹅掌楸属Liriodendron L.的花粉除了进行光学显微镜及扫描电镜的观察外,还借助透射电镜对其花粉壁作了深入的超微结构研究。研究结果表明:1)分布于东亚和北美的种类有截然不同的外壁纹饰。东亚种为穴网状纹饰;北美种为皱疣状纹饰。2)纹饰特征可作为区分这两个从形态学上难以区分的“种对”的可靠依据。3)根据花粉壁纹饰的演化规律,表明具穴网状纹饰的“鹅掌楸”L.chinense较之具皱疣状纹饰的“北美鹅掌楸”L.tulifera更为原始。4)从花粉壁的超微结构看,鹅掌楸属花粉外壁可明显区分为复盖层和柱状层,而木兰科其它大多数类群的花粉外壁尚无明显结构分化,即未分化成明显的复盖层和柱状层,仅有复盖一颗粒状结构的分化。根据花粉壁的演化过程是从无结构向有结构层分化这一规律,说明鹅掌楸属是木兰科中较为进化的类群。并且由于其外壁结构与木兰科大多数其它类群的外壁结构表现出如此大的差异,孢粉学上支持把鹅掌楸属作为木兰科中的亚科处理。
Exine sculpture of pollen grains is the distinctive and reliable character to classify the two species of Liriodendron L.i.e., L. chinense with foveolate-reticulate sculpture and L. tulipifera with rugulate-verrucate sculpture. According to the evolution of pollen sculpture, the foveolate?reticulate pollen of L. chinense is more primitive than the rugulate-verrucate pollen of L. tulipifera. Ultrastructure of pollen wall shows that the tectate-columellae pollen of Liriodendron is rarer structure type within Magnoliaceae and is more advanced than the atectate type and tectate-granular structural type of most taxa of Magnoliaceae. Palynology supports to treat the genus Liriodendron as a subfamily.
出处
《云南植物研究》
CSCD
1993年第2期163-166,共4页
Acta Botanica Yunnanica
关键词
鹅掌楸属
花粉
形态
超微结构
Liriodendron
Pollen morphology
Ultrastructure
