国产山龙眼科花粉形态及外壁超微结构的研究

POLLEN MORPHOLOGY AND WALL ULTRASTRUCTURE OF PROTEACEAE IN CHINA

对国产山龙眼科的山龙眼屑Helicia Lour,假山龙眼属Heliciopsis Sleum,及引种的银桦属Grevillea R,Br.共13种的花粉形态进行了光镜及电镜的观察研究。着重比较了花粉表面的纹饰特征及花粉壁的结构层次和各层的厚度及其比例。山龙眼属的花粉具粗糙-颗粒状纹饰,外壁较薄,仅1—1.2/μm,其中复盖层0.3—0.4μm,柱状层0.15—0.2pm,基层0.5—0.6μm。假山龙眼属的花粉具网状纹饰,外壁厚达2.5—3μm,为前一属外壁厚度的2倍多,其中复盖层0.5—O.7μm,柱状层及基层分别为0.8—1μm及1—1.5pm,均比山龙眼属的厚得多。孢粉学上支持Sleumer H.的观点,将原隶属于山龙眼属的具此特征的一些种独立出来建立假山龙眼属。假山龙眼属的花粉形态及外壁超微结构特征与分类系统上疏远的、被Johnson置于山龙眼科不同亚科的Sphalmium属和Carnarvonia屑的具有很大的相似性,表现在具有网状的外壁纹饰,厚的外壁层及基层。由此作者认为,似乎有必要进一步对该科相关属的花粉作深入的对比研究,并吸收其它学科的资料,以便对它们的亲缘关系问题作出合理的处理或重新考虑其系统安排。银桦属的花粉与山龙眼属及假山龙眼属的差异较大,表明其关系疏远。

This paper examined pollen grains of Helicia Lour., Heliciopsis Sleum. and Grevillea R. Br. with LM, SEM and TEM. The result showed that the exine sculpture and the thickness of various wall layers of Heliciopsis , on the one hand, are different from these of Helicia, the former with reticulate sculpture and thicker wall layers(tectum 0.5-0.7um, columellae 0.8-1um, foot layer 1-1.5um, the total exine 2.5-3um), the latter with scabrate-granulate sculpture and thinner wall layers(tectum 0.3-0.4um, columellae 0.15-0.2um, foot layer 0.5-0.6um, the total exine only 1-1.2um), and on the other hand are similar to those of Sphalmium and Carnarvonia, both of which also have reticulate sculpture and thicker wall layers. Palynology supports Sleumer's view to separate Heliciopsia from Helicia. Heliciopsis, Sphalmium and Carnarvonia are remotely related in Johnson's system, but because of their similarity of pollen morphology including exine sculpyure and the thickness of various wall layers, it seems necessary to reconsider their phylogenetic relationships by further study of other related genera, especially those ofGrevilleoideae of Proteaceaeand at the same time incorporation other data on various subjects.