Ontogeny and Vascularization Elucidate the Atypical Floral Structure of Ampelocera glabra, a Tropical Species of Ulmaceae

Autor(en)
Flávia M. Leme, Yannick M. Staedler, Jürg Schönenberger, Simone P. Teixeira
Abstrakt

Premise of research.?Ampelocera glabra is an andromonoecious, wind-pollinated species of Ulmaceae, the elm family. This family comprises two clades: tropical and temperate. The species that have been morphologically studied so far all belong to the temperate clade. Ampelocera glabra is included in the tropical clade and is remarkable due to its atypical flower merism when compared to other Ulmaceae and to most other rosids: tetramerous calyx, polyandrous androecium, and pseudomonomerous gynoecium. Thus, our objective was to study the ontogeny and vascularization of the A. glabra flower to elucidate the processes involved in the atypical merism and in the reduced structure of the whorls. Additionally, the mating system of A. glabra was checked and its floral structure was associated with anemophily, thus contributing to reproductive studies of this species under threat of extinction.Methodology.?Flowers and early to late floral buds were processed for surface (SEM) and histological (LM) investigations and 3D reconstructions (X-ray microcomputed tomography).Pivotal results.?Ampelocera glabra is actually a monoecious species with functionally staminate and functionally pistillate flowers, containing carpellodes and staminodes, respectively. The single perianth whorl is composed of sepals, and there is no hypanthium. Each primordium of the sepals and stamens arises individually. A central common primordium gives rise to two carpels, but only one houses an ovule. Each carpel is vascularized by one dorsal bundle, and the carpel that bears the ovule is also vascularized by one ventral bundle. Thus, the gynoecium displays a reduction in the vascular bundle in the nonovulate carpel.Conclusions.?The differences in merism between the calyx and the androecium are explained by the space that can support the increase in organ number. The increase in stamen number and the reduced gynoecium (pseudomonomerous) enable a high pollen?ovule ratio, which is an important condition for any anemophilous species.

Organisation(en)
Department für Botanik und Biodiversitätsforschung
Externe Organisation(en)
Universidade de São Paulo, Universidade Federal de Mato Grosso do Sul
Journal
International Journal of Plant Sciences
Band
179
Seiten
461-476
Anzahl der Seiten
16
ISSN
1058-5893
DOI
https://doi.org/10.1086/697899
Publikationsdatum
04-2018
Peer-reviewed
Ja
ÖFOS 2012
106008 Botanik, 106012 Evolutionsforschung, 106042 Systematische Botanik
Schlagwörter
ASJC Scopus Sachgebiete
Ecology, Evolution, Behavior and Systematics, Plant Science
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/ontogeny-and-vascularization-elucidate-the-atypical-floral-structure-of-ampelocera-glabra-a-tropical-species-of-ulmaceae(eaec617a-ceed-4b4f-97af-dd8f2218ac6b).html