19种菊科植物花药结构及绒毡层的发育类型研究

花药结构和绒毡层的发育类型对菊科植物的系统分类和系统演化具有重要的意义。本研究采用苏木精和苯胺番红整体染色以及石蜡切片的方法,通过显微镜观察,对菊科7族19属19种植物花药结构及绒毡层的发育类型进行研究。结果表明,18种植物的花药由4个花粉囊组成,1种由2个花粉囊组成。花粉囊壁由表皮、药室内壁、中层和绒毡层4层细胞组成,中层细胞在花粉母细胞时期解体。随着花粉粒的形成,药室内壁先“U”形增厚,再进行条带状增厚。花粉母细胞胞质分裂类型有连续型和同时型2种,小孢子四分体以四面体形为主。绒毡层的发育类型有变形绒毡层和分泌绒毡层两种类型,变形绒毡层是管状花亚科植物的共同特点,分泌绒毡层是舌状花亚科植物的共同特点。从向日葵族向菊苣族的逐渐演化过程中,绒毡层的发育类型从向日葵族的变形绒毡层、经过变形绒毡层向分泌绒毡层的过渡类型逐渐演化为菊苣族的分泌绒毡层。变形绒毡层的形态在管状花亚科不同族之间有明显差异,绒毡层的发育类型和形态可以作为亚科和族分类的依据之一。

Anther structures and tapetum development types of 19 species of Asteraceae

Anther structure and tapetum developmental type is important for systematic classification and understanding of the evolution of the Asteraceae. In this work, anther structures and tapetum development types of 19 species in 19 genera of the Asteraceae were investigated by paraffin sections, hematoxylin integral staining, aniline-saffron integral staining and microscopic observation. It was found that the anther structures of all species examined consist of four clinandria except for one containing two. The anther wall consists of four layers of cells, namely: the epidermis, endothecium, middle layer and the tapetum layer. The middle layer cells disintegrate in the meiocyte period. During formation of pollen grains, the endothecium thickens in a U-shaped manner initially, followed by band-shaped thickening. The microspore mother cells have two types of cytokinesis, a continuous type and a simultaneous type. The majority of the microspore tetrads are tetrahedral. The tapetum has two types, an amoeboid type, characteristic of the Carduoideae, and a glandular type, a feature of the Cichorioideae. From an evolutionary perspective, a progression of three tapetal developmental types is evident: the amoeboid tapetum of the Heliantheae, a transitional type from amoeboid tapetum to glandular tapetum and glandular tapetum in the Lactuceae. The morphologies of the amoeboid tapetum are obviously different among the various species. The developmental type and morphology of the tapetum are important characteristics in Asteraceae classification.