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Made available in DSpace on 2019-10-06T15:48:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-08-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Mayacaceae are a small and monogeneric aquatic family including 4–6 species and with an unstable phylogenetic position within Poales. Therefore, the floral development and vasculature were studied in Mayaca fluviatilis and Mayaca sellowiana to better understand interfamilial relationships. In both species, the floral vascular system is organized in six central complexes from which the traces of all floral parts diverge. Both sepals and petals receive three traces, but in the sepals the median and lateral traces do not originate from the same vascular complex, whereas in the petals the median and lateral traces originate from the same complex. Both, ventral and dorsal carpellary traces, vascularize the ovary wall, ascending to the stigma. The sepals are the first organs to be initiated and have a rapid growth. Such structures exhibit glandular trichomes on their margins and remain united, protecting the inner whorls. After sepal development, the petals and the stamens of the outer whorl are initiated, followed by the gynoecium, which appears as an annular primordium. The petals have a markedly delay in development. In M. fluviatilis, the anthers may dehisce before anthesis and self-pollination occurs in the bud. The reduction (loss) of the inner stamen whorl and gynoecium development from an annular primordium link Mayacaceae to the cyperids (Poales). A high similarity in respect to floral vasculature was observed between Mayacaceae and Commelinaceae (Commelinales). Programa de Pós-Graduação em Ciências Biológicas (Biologia Vegetal) Departamento de Botânica Instituto de Biociências UNESP - Universidade Estadual Paulista, C. Postal 199 Programa de Pós-Graduação em Ciências Biológicas (Biologia Vegetal) Departamento de Botânica Instituto de Biociências UNESP - Universidade Estadual Paulista, C. Postal 199 CNPq: 168277/2014-0 CNPq: 301692/2010-6

Made available in DSpace on 2021-06-25T10:15:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-01 Mapanioideae (besides Cyperoideae the other subfamily of Cyperaceae) is divided in two tribes (Hypolytreae and Chrysitricheae) in which the reproductive units (spicoids) are interpreted either as flowers or as inflorescences. Little is known about the ontogenetic factors operating during the spicoid development and how they may contribute to the spicoid final morphology. In this context, we studied the spicoid development in the monotypic genus Diplasia and compared it with other developmental studies in Mapanioideae. Our results show that the main developmental variations are related to the sequence of organ formation, the size and shape of the spicoid primordium and the influence of the subtending bract constraints in different sides of such primordium. Our hypotheses to explain the spicoid’s morphological variation in Mapanioideae are: that size and shape of the spicoid primordium contribute to changes in the number and position of organs to be formed, and spatial constraints of the subtending bracts influence the reduction of adaxial parts. Developmental features of the spicoids showed to be stable within the tribe. Our observations of the nature of spicoids in Diplasia give arguments for both, floral and inflorescence interpretations, sustaining the uncertainty towards a satisfactory definition. The difficulty in distinguishing the boundaries of flower and inflorescence nature in the spicoids raised a third hypothesis where the spicoid could be interpreted as a de novo structure, due to a reorganisation of regulatory genes resulting in a single unit with flower and inflorescence features combined, considered a synapomorphy of Mapanioideae. Departamento de Botânica Instituto de Biociências Universidade de São Paulo Departamento de Botânica Instituto de Biociências Universidade Estadual Paulista (UNESP), Caixa Postal 199 Jodrell Laboratory Royal Botanic Gardens Departamento de Botânica Instituto de Biociências Universidade Estadual Paulista (UNESP), Caixa Postal 199

Made available in DSpace on 2018-12-11T16:44:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-03-01 Rhynchospora is one of the most species-rich genera of Cyperaceae and one of the few with entomophilous species. Considering the few anatomical studies of the genus, especially of the reproductive structures, this study comparatively analysed the anatomy of flowers of two representative species of Rhynchospora, R. consanguinea and R. pubera, including the floral vasculature and the anatomy of the style base, which is persistent with the fruit. Both species have congested inflorescences with light-coloured bracts and bisexual flowers, and phenolic idioblasts in the anthers and gynoecium, characteristics that suggest insect pollination. In R. consanguinea, the bisexual and the most proximal male flower has perianths, a new character state reported for the genus. The floral vasculature pattern is similar in both species, but differs from that previously described for Rhynchospora. In both species, there are two vascular bundles in the rachilla, which split into three receptacular bundles, the latter forming a vascular plexus where the bundles of stamens, gynoecium and ovule are connected. No lateral carpellary trace was observed, and the presence of the abaxial receptacular bundle was interpreted as a vestige of the tricarpellate ancestral condition. In the fruit of both species, the thickened style base (stylopodium) has a parenchyma with idioblasts containing phenolic compounds and idioblasts with helical or reticulate cell wall thickenings. The stylopodium is a homologous structure in the species of Rhynchospora and to other genera of Cyperoideae and evolved several times in the subfamily. Departamento de Botânica Instituto de Biociências Universidade Estadual Paulista (UNESP), Caixa Postal 199 Departamento de Botânica Instituto de Biociências Universidade Estadual Paulista (UNESP), Caixa Postal 199