中国五加科花粉形态研究

本文对我国五加科(Araliaceae)植物21个属、34种、2变种的花粉形态进行了详细的观察研究, 每一个属均选择1至2个代表种进行电镜扫描。从花粉学方面进一步探讨了各属间的亲缘关系, 分类位置、以及分属的界限等问题。

POLLEN MORPHOLOGY OF THE FAMILY ARALIACEAE IN CHINA

The pollen grains of 34 species and 2 varieties in Araliaceae from China, were examined by light microscope and in which 22 species rep-resenting 21 genera of the family by scanning electron microscop. Theircharacteritic details are given in the generic diagnosis. According to their shape, form and sculpture of exine etc., these genera can be distinguished except Tupidanthus and Schefflera, because they have similar pollen characteritic. A pollen key to the genera based on these observations is presented. 1. based on the shape of pollen grains can be grouped the followingmain three types:(1). Spheroidal type (P/E=0.88-1.14):Trevesia, Fatsia, Oplopanax, Merrilliopanax, Nothopanax. (2). Subprolate type (P/E=1.14-1.33):Hedera, Tetrapanax, Sincpanax. (3). Prolate type (P/E=1.33-2):Kalopanax, Tupidanthus, Heteropanax. The shape of some pollen grains in the genera with many species isvariable such as Schefflera, from subprolate to prolate, Acanthopanax, from spheroidal to subprolata etc. 2. Based on the sculpture and structure of exine four types can be also grouped:(1). Tuberculate or clavate type:Fatsia, Trevesia. (2). Reticulate type:three forms A. Fine-reticulate form:The tectum is psilate or the lumina is incouspicuous as Merrilliopanax, . B. Middle-reticulate form. The lumina with 0.5-1.5μ in. diam. as Aralia, Acanthopanax. C. Crass-reticulate form. The lumina is over 1.5μ in diam. as Kalopanax, Panax Hedera. (3). Interrupted-tectum type:only in Osmoxylon. (4). Areolate type:only in Diplopanax. In this paper are discussed some taxonomic problems:The characteritic of pollen between the Brassaiopsis and Euaxaliopsis is so similar that it is impossible to separate it into two genera. specialized pollen grains and the large fruit with One-seed (Locule) of the genus Diplopanax Hand.Mazz. indicate that this genus does'nt belong to Araliaceae or Cornaceae, but to Aralidiaceae. The evidence of the pollen, and other morphological features as racemose inflorescences, evergreen trees support that it is best to separate Parapentapanax Hutch. from the Pentapanax Seem. Finally, According to each pollen type and correlation with othermorphological characters (see table 2), a proposed scheme of phylogene-tic relationships of the genera in Araliaceae from China is shown in Fig.I. by author.