Comparative embryology and taxonomic considerations in Eriocaulaceae (Poales)

International Journal of Plant Sciences

2012

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Xyridaceae, Eriocaulaceae, and Mayacaceae form the xyrid clade, which is weakly supported in Poales. The floral anatomy of xyrid species was studied, to contribute to the understanding of the relationships within the group. Both Eriocaulaceae and Xyridaceae have petals with elongated epidermal cells with straight walls, epipetalous stamens, staminodes, anthers with longitudinal dehiscence, an endothecium with band-like thickenings, and a style vascularized by the dorsal carpellary bundles; these characteristics thus corroborate the close relationship of these groups indicated by phylogenetic analyses. Mayacaceae is distinguished by the presence of papillose epidermal cells in the petals, a reduced inner whorl of stamens, poricidal anthers, an endothecium lacking thickenings, a style and stigma vascularized by the dorsal and ventral carpellary bundles, and the presence of an obturator in the ovary wall. A reduction in the inner whorl of fertile stamens also occurs in Juncaceae and Cyperaceae, linking Mayacaceae to the cyperids. The stylar appendages of Orectanthe (Xyridaceae) have been shown to be nectariferous and anatomically similar to those of Abolboda, differentiating these two genera from Xyris (Xyridoideae) and confirming their placement in Abolbodoideae. Stylar appendages also occur in Eriocaulaceae, with the same function, position, and vascularization, and are therefore homologous structures, reinforcing the phylogenetic proximity between Eriocaulaceae and Xyridaceae.

Section: Discussionmentioning

confidence: 99%

Floral Anatomy of Xyrids (Poales): Contributions to Their Reproductive Biology, Taxonomy, and Phylogeny

Oriani

International Journal of Plant Sciences

2012

“…Successive microsporogenesis occurs in Xyridaceae, Eriocaulaceae (Scatena and Bouman 2001;Coan et al 2010), and Mayacaceae (Venturelli and Bouman 1986) and is a predominant condition in monocotyledons. Simultaneous microsporogenesis occurs in Asparagales, in some taxa of Araceae, Alismatales, and Dioscoreales, and in the commelinid clade (Furness and Rudall 1999b), and it probably evolved independently several times within monocotyledons (Furness et al 2002).…”

Section: Discussionmentioning

confidence: 99%

Anther Wall Development, Microsporogenesis, and Microgametogenesis inAbolbodaandOrectanthe: Contributions to the Embryology of Xyridaceae (Poales)

Oriani

International Journal of Plant Sciences

2015

Editor: Patrick S. Herendeen Premise of research. Xyridaceae includes two subfamilies with a total of five genera. Xyridoideae has only the single genus Xyris, and Abolbodoideae includes the remaining genera. The inter-and intrafamilial relationships among Xyridaceae have not yet been clarified, and this study therefore aimed to investigate the anther wall and pollen grain development in Abolboda and Orectanthe species, searching for characters that can be used in taxonomic and phylogenetic analyses.Methodology. Anthers from flowers at different stages of development were examined using both LM and SEM.Pivotal results. All studied species present the following: monocotyledonous type of anther wall development, single-layered endothecium with band-like thickenings in the mature anther, single ephemeral middle layer, multilayered and plasmodial tapetum, successive microsporogenesis, and spherical inaperturate pollen grains. Characteristics such as reduced type of anther wall development, single-layered and secretory tapetum with uninucleate or binucleate cells, and elliptical sulcate pollen grains with a reticulate exine are present in Xyris and differentiate this genus from Abolboda and Orectanthe. The characteristics reported for Xyris are also present in Mayacaceae, which used to form the xyrid clade of Poales with Eriocaulaceae and Xyridaceae. Abolboda and Orectanthe share with Eriocaulaceae the monocotyledonous type of anther wall development with an ephemeral middle layer, an endothecium with band-like thickenings, and pollen grain exine with projections. The presence of a multilayered tapetum is exclusive to Abolboda and Orectanthe among the Xyridaceae and also among the Poales.Conclusions. The embryological characteristics support the division of Xyridaceae into two subfamilies. In contrast with the megasporogenesis and megagametogenesis, the microsporogenesis and microgametogenesis characteristics were quite variable within the xyrid clade, with successive microsporogenesis being the only characteristic shared by Xyridaceae, Eriocaulaceae, and Mayacaceae.

“…En Eriocaulaceae la endotesta se origina a partir de la capa interna del tegumento externo, el cual presenta células cuyas paredes periclinales y anticlinales se espesan formando diferentes ornamentaciones (Scatena & Bouman, 2001;Coan et al, 2010). Esta capa, junto con el endotegmen, que se origina de la capa interna del tegumento interno, es la cubierta seminal patrón en Eriocaulaceae (Coan et al, 2010).…”

Section: Discusión Las Características De Las Semillas Deunclassified

“…Los caracteres de la cubierta seminal en Eriocaulaceae son de utilidad taxonómica a nivel genérico (Nair, 1987;Giulietti, Monteiro, Mayo, & Stephens, 1988;Coan, Stützel, & Scatena, 2010;Zona, Davis, Gunathilake, Prince, & Horn, 2012). También diferencian Comanthera subg.…”

unclassified

“…Thysanocephalus (Barreto, Echternacht, & García, 2013). Los datos embriológicos y de desarrollo de semillas no permiten diferenciar entre los géneros (Ramaswamy, Arekal, & Raju, 1983;Scatena & Bouman, 2001;Coan et al, 2010), pero la ornamentación de la cubierta seminal es específica (Coan et al, 2010). De esa forma, son necesarios estudios de morfología de semillas y desarrollo post-seminal con representantes de Eriocaulaceae dada su importancia taxonómica.…”

unclassified

See 1 more Smart Citation

Seed morphology and post-seminal development in species of Comanthera (Eriocaulaceae)

Corredor

Escobar

2015

RBT

Seed morphology and post-seminal development in species of Comanthera (Eriocaulaceae). Comanthera brasiliana, C. magnifica and C. suberosa (Eriocaulaceae) are included in the Brazilian list of endangered species, due to intensive harvest and micro-endemism. These species form the clade of Comanthera magnifica, along with C. brunnea and C. linearis. Germination, seed morphology and post-seminal development were studied aiming to characterize all five species and to provide information for their conservation. Seeds were collected in "campos rupestres" of Minas Gerais, Brazil. Seed morphology was examined using scanning electron microscope. For germination tests, mature seeds were placed in Petri dishes lined with filter paper dampened with distilled water at 25 °C and fluorescent light; four repetitions with 15 seeds were performed for each species. For the anatomical analysis of post-seminal development, seedlings at different developmental stages were included in historesin, cut with a rotatory microtome and examined under a light microscope. The structure of the seed coat and the shape and size of the seeds were characteristics that allowed species differentiation, and based on the seeds morphological characteristics, an identification key is provided. The seed germination was high (> 90 %) and fast (< 7 days). Germination occured through the axis protrusion of the embryo. Approximately four days after germination, the first leaf develops and is followed by the adventitious roots. After 10-15 days, the second leaf and the new adventitious roots develop. In field conditions, the studied species occur in quartzite soils and their small seeds (dust-like type) germinate faster than the other Eriocaulaceae species (from mesic soils). These results provide reliable information that may contribute to the species management and conservation. Rev. Biol. Trop. 63 (4): 1127-1135. Epub 2015 December 01.