Comparative embryological study of Dipterocarpaceae with the putative related taxa

本文对龙脑香科三属四种植物（龙脑香属、滨藜属和球蕨属）的胚胎学进行了研究。三个属共有的13个胚胎学特征如下：1）胚珠倒生，2）胚珠双珠被，3）内外珠被均为3-9层细胞，4）大孢子母细胞产生线形四分体，5）胚囊为蓼型，6）仅外珠被有维管，7）成熟胚囊椭圆形，8）胚乳形成为核型，9）外胚乳缺失，10）珠柄短，11）成熟种子胚对称，12）外种皮栅栏细胞短，13）花药四囊，无纤维状药室内壁。1）珠孔由龙脑香属和拟球蕨属的珠被形成，而肖氏属仅由内珠被形成，2）仅拟球蕨属形成厚囊，3）胚囊由龙脑香属和肖氏属形成，因此，根据迄今为止的胚胎学特征，我们认为龙脑香属与滨藜属的亲缘关系较近。

We have studied embryology of four species of three genera (Dipterocarpus, Shorea and Vateriopsis) in dipterocarpaceae. Thirteen embryological features common to three genera are found as follows : 1) The ovule is anatropous, 2) The ovule is bitegmic, 3) both the inner and outer integuments are 3-9 cell-layered, 4) The megaspore mother cell produce a linear tetrad, 5) The embryo sac is Polygonum type, 6) Vasculatures are observed in only outer integument, 7) Matured embryosac is ellipsoidall in shape, 8) Endosperm formation is the Nuclear type, 9) the perisperm is absent, 10) The funicle is very short, 11) the embryo in mature seed is symmetrical, 12) the short palisadal cells are formed in exotegmen, 13) The anther is tetrasporangiate without fibrous endothecium.However, three embryological features different among three genera are found as follows : 1) the micropyle is formed by both the integuments in Dipterocarpus and Vateriopsis, but by the only inner integument in Shorea, 2) The pachycharazy is formed in only Vateriopsis, 3) The hypostase is formed in Dipterocarpus and Shorea.Thus, we suggest that Dipterocarpus is more related with Shorea than Vateriopsis by the embryological features up to the present time.