关键词: 菊科, 花药结构, 分泌绒毡层, 变形绒毡层, 分类

Abstract: 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.

Key words: Asteraceae, anther structures, glandular tapetum, amoeboid tapetum, classification