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- Title
A contribution to the knowledge of the exine, with special reference to the ultrastructure, in subtribe Ecliptinae (Heliantheae, Asteraceae).
- Authors
Coutinho, António; Valente, Mariana; França, Rita; Perpétuo, Natacha; Kanoun-Boulé, Myriam; Gouveia, Márcia; Soares, Margarida; Borges, Joana; Currais, Lara
- Abstract
The exine morphology, with emphasis on the ultrastructure, of six genera and species of Ecliptinae was studied with transmission electron microscopy and scanning electron microscopy. A caveate exine with a single layer of columellae and predominantly circular to sub-circular internal foramina (Helianthoid pattern of structure) is present in all the studied taxa and most probably in all the Ecliptinae. The morphologies of the internal foramina and foot layer are consistent within the Ecliptinae, and their potential taxonomic and phylogenetic relevance was discussed. The existence, for almost all the investigated characters and ratios, of a continuous gradient among the taxa, exists in the wedelioid group and constitutes a quite well defined parallelism between the exine data and those of the major clade of Ecliptinae (wedelioid group). The exine sculpture of the worldwide weed Eclipta prostrata (L.) L. presents some variation, which is, most probably, correlated to the existence of geographical clines and/or variations in its chromosome number. A mesoaperture concerning the foot layer and the upper part of the endexine exists in all the taxa studied and, presumably, in all the Ecliptinae, probably constituting a synapomorphy for all the Asteroideae and possibly for all the Asteraceae.
- Subjects
ASTERACEAE; SCANNING electron microscopy; TRANSMISSION electron microscopy; PHYLOGENY; POLLEN
- Publication
Plant Systematics & Evolution, 2016, Vol 302, Issue 9, p1207
- ISSN
0378-2697
- Publication type
Article
- DOI
10.1007/s00606-016-1326-2