山茶属的花粉形态及其分类学意义

POLLEN MORPHOLOGY OF CAMELLIA(THEACEAE) AND ITS TAXONOMIC SIGNIFICANCE

本文对山茶属(Camellia L.)18个组27个代表种的花粉进行了光学显微镜、扫描电镜和大部分进行了透射电镜的观察,并对花粉大小、形状、外壁纹饰和超微结构等作了综合的比较。结果表明,其形状和大小差异不很明显。花粉壁的层次、厚度和不同层次的比例,如复盖层与柱状层以及外壁外层与外壁内层的比例等也没有显著的差异。但花粉壁的纹饰特征在扫描电镜下显示出较大的差异,具有较重要的分类学价值。根据其纹饰特征,可以把山茶属花粉大致区分为六个类型:皱疣状纹饰;粗瘤状纹饰;颗粒状至皱-颗粒状纹饰;穴-网状纹饰;皱沟状纹饰及皱波-念珠状纹饰。孢粉学上区分的类型不完全与各个学者从植物形态上划分的组相一致。其中管蕊茶 Camellia lanceolata的纹饰非常特殊(粗瘤状),其外壁表面很象牛心果(Annona reticulata)的外形特征,为其重新分类提供孢粉学依据。

Pollen grains of 27 species representing 18 sections of Camellia have been examined by light microscope (LM), scanning electron microscope (SEM) and mostly by transmission electron microscope (TEM). From the comparison of pollen size and shape, the exine sculpture, the pollen wall ultrastructure and exine stratification, we divided the pollen grains of Camellia into 6 types: 1. rugulate-verrucate; 2. coarsely warty; 3. granulate to rugulate-granulate; 4.foveolate-reticulate; 5. rugulate-fossulate; and 6. rugulate with beaded muri. These types are not in keeping with the sections divided morphologically by Mechior (1925), by Sealy J.R. (1950) or by Chang Hungta (1981-1982).