9 results on '"Sajo, Maria das Graças"'
Search Results
2. Floral development and vasculature in Eriocaulon (Eriocaulaceae) provide insights into the evolution of Poales.
- Author
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Silva, Arthur de Lima, Trovó, Marcelo, Stützel, Thomas, Rudall, Paula J, Sajo, Maria das Graças, and Coan, Alessandra Ike
- Subjects
POLLINATORS ,FLORAL morphology ,POLLINATION ,BLOOD vessels ,BIOLOGICAL evolution ,SCANNING electron microscopy ,NECTARIES - Abstract
Background and Aims Floral developmental studies are crucial for understanding the evolution of floral structures and sexual systems in angiosperms. Within the monocot order Poales, both subfamilies of Eriocaulaceae have unisexual flowers bearing unusual nectaries. Few previous studies have investigated floral development in subfamily Eriocauloideae, which includes the large, diverse and widespread genus Eriocaulon. To understand floral variation and the evolution of the androecium, gynoecium and floral nectaries of Eriocaulaceae, we analysed floral development and vasculature in Eriocaulon and compared it with that of subfamily Paepalanthoideae and the related family Xyridaceae in a phylogenetic context. Methods Thirteen species of Eriocaulon were studied. Developmental analysis was carried out using scanning electron microscopy, and vasculature analysis was carried out using light microscopy. Fresh material was also analysed using scanning electron microscopy with a cryo function. Character evolution was reconstructed over well-resolved phylogenies. Key Results Perianth reductions can occur due to delayed development that can also result in loss of the vascular bundles of the median sepals. Nectariferous petal glands cease development and remain vestigial in some species. In staminate flowers, the inner stamens can emerge before the outer ones, and carpels are transformed into nectariferous carpellodes. In pistillate flowers, stamens are reduced to staminodes and the gynoecium has dorsal stigmas. Conclusions Floral morphology is highly diverse in Eriocaulon , as a result of fusion, reduction or loss of perianth parts. The nectariferous carpellodes of staminate flowers originated first in the ancestor of Eriocaulaceae; petal glands and nectariferous branches of pistillate flowers originated independently in Eriocaulaceae through transfer of function. We present a hypothesis of floral evolution for the family, illustrating a shift from bisexuality to unisexuality and the evolution of nectaries in a complex monocot family, which can contribute to future studies on reproductive biology and floral evolution in other groups. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
3. Evolutionary lability in floral ontogeny affects pollination biology in Trimezieae.
- Author
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Lovo, Juliana, Alcantara, Suzana, Vasconcelos, Thais N. C., Sajo, Maria das Graças, Rudall, Paula J., Prenner, Gerhard, Aguiar, Antônio J. C., and Mello‐Silva, Renato
- Subjects
ONTOGENY ,DEVELOPMENTAL biology ,FLORAL morphology ,BIOLOGY ,POLLINATION by bees ,POLLINATORS ,POLLINATION - Abstract
Premise: There is little direct evidence linking floral development and pollination biology in plants. We characterize both aspects in plain and ornamented flowers of Trimezieae (Iridaceae) to investigate how changes in floral ontogeny may affect their interactions with pollinators through time. Methods: We examined floral ontogeny in 11 species and documented pollination biology in five species displaying a wide range of floral morphologies. We coded and reconstructed ancestral states of flower types over the tribal phylogeny to estimate the frequency of transition between different floral types. Results: All Trimezieae flowers are similar in early floral development, but ornamented flowers have additional ontogenetic steps compared with plain flowers, indicating heterochrony. Ornamented flowers have a hinge pollination mechanism (newly described here) and attract more pollinator guilds, while plain flowers offer less variety of resources for a shorter time. Although the ornamented condition is plesiomorphic in this clade, shifts to plain flowers have occurred frequently and abruptly during the past 5 million years, with some subsequent reversals. Conclusions: Heterochrony has resulted in labile morphological changes during flower evolution in Trimezieae. Counterintuitively, species with plain flowers, which are endemic to the campo rupestre, are derived within the tribe and show a higher specialization than the ornamented species, with the former being visited by pollen‐collecting bees only. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
4. Anatomia de raízes e rizomas de 14 espécies de Bromeliaceae
- Author
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Proença, Suzana Lúcia [UNESP], Sajo, Maria Das Graças [UNESP], and Universidade Estadual Paulista (Unesp)
- Subjects
cerrado ,bromélias ,Bromelioideae ,Pitcairnioideae ,Tillandsioideae ,water capture ,captura de água ,retenção hídrica ,bromeliads ,'cerrado' ,water retention - Abstract
Made available in DSpace on 2021-07-14T10:54:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2008. Added 1 bitstream(s) on 2021-07-14T11:40:53Z : No. of bitstreams: 1 S2175-78602008000100113.pdf: 297295 bytes, checksum: 2cd6056c5fb44bf730cbcaca565068ed (MD5) Com o objetivo de reconhecer caracteres particulares de Bromeliaceae e indicar possíveis formas de adaptação ao ambiente, foi estudada a anatomia dos rizomas e raízes de 14 espécies de Bromeliaceae que ocorrem no cerrado. Os rizomas apresentam estrutura básica semelhante, embora alguns deles possuam porções radiculares crescendo no interior de seu córtex. De acordo com a espécie considerada, os rizomas podem apresentar um cilindro vascular de delimitação mais ou menos nítida. As raízes também possuem estrutura básica semelhante, apesar do tecido de revestimento variar de acordo com a porção analisada (dentro do rizoma ou externa). Além disso, as raízes apresentam uma região cortical de organização variada, de acordo com a região do órgão, e um cilindro vascular. Muitos dos caracteres anatômicos observados estão associados a mecanismos de captação e retenção hídrica, mostrando que as espécies estudadas estão adaptadas ao ambiente de cerrado. The anatomy of rhizomes and roots of 14 species of Bromeliaceae that occur in the cerrado biome were studied with the aim of pointing out particular anatomical features of the family and possible adaptations related to the environment. All the rhizomes are similar although some have root regions growing inside the cortex. In some species the vascular cylinder of the rhizome is clearly limited from the cortex. The roots are also very similar, although the coating tissue differs in roots growing inside the rhizome or externally to it and the cortex has a variable organization according to the region. The studied species present anatomical features that are associated to water absorption and storage, showing that they are adapted to the cerrado environment. Universidade Estadual Paulista, Instituto de Biociências Universidade Estadual Paulista, Instituto de Biociências
- Published
- 2008
5. Microsporogenesis is simultaneous in the early-divergent grass Streptochaeta, but successive in the closest grass relative, Ecdeiocolea.
- Author
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Sajo, Maria Das GraÇas, Furness, CarolA., and Rudall, PaulaJ.
- Subjects
- *
STREPTOCHAETA , *GRASSES , *POLLEN , *POLLINATION , *PLANTS - Abstract
Simultaneous microsporogenesis is described for the first time in a grass, Streptochaeta spicata Schrad., a tropical Brazilian species that belongs in the early-divergent subfamily Anomochlooideae. Microsporogenesis is successive in all other Poaceae examined so far, and most other members of the order Poales, to which grasses belong. The only other reports of simultaneous microsporogenesis in Poales are in Rapateaceae and some members of the cyperid clade (Juncaceae, Cyperaceae, Prionium and Thurnia). Among the graminids, Ecdeiocolea (the putative closest relative to Poaceae) is successive, as are Joinvillea, Flagellaria and all other Poaceae, indicating that the simultaneous condition is autapomorphic in Streptochaeta, though Anomochloa has yet to be examined. Anther wall development in Streptochaeta is of the reduced type, as also in another early-divergent grass Pharus, though most other Poales, including most grasses, have the monocot type. In Streptochaeta, as in Pharus, the endothecium lacks thickenings, unlike other grasses that have a persistent endothecium with thickenings. The centrifixed anthers and nonplumose stigmas of Streptochaeta suggest entomophily. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
6. Floral anatomy of Neotropical species of Mayacaceae
- Author
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de Carvalho, Maria Luiza Silveira, Nakamura, Adriana Tiemi, and Sajo, Maria das Graças
- Subjects
- *
MAYACACEAE , *COMMELINALES , *FLORAL products , *PLANT reproduction - Abstract
Abstract: The Mayacaceae are a monogeneric monocot family of herbs that grow on swampy areas in the Americas and in Africa. Both the number of species constituting the family and its inter-familial relationships are unclear. By describing and comparing the floral anatomy of Mayaca fluviatilis, M. fluviatilis f. kunthii, M. longipes and M. sellowiana we have identified some features that delimit the species. These include: arrangement of flowers on the stem, shape of stamens, size of apical pores, disposition of microsporangia, number of ovules and shape of the stylar canal. We concluded that M. fluviatilis f. kunthii should be considered as a species (M. kunthii) rather than a forma. Other characters such as number of stamens and microsporangia, placentation, ovule type and cell numbers in the pollen grain support the placement of the Mayacaceae within Poales. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
7. Floral development and vasculature in Eriocaulon (Eriocaulaceae) provide insights into the evolution of Poales.
- Author
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de Lima Silva A, Trovó M, Stützel T, Rudall PJ, Sajo MDG, and Coan AI
- Subjects
- Flowers, Microscopy, Electron, Scanning, Phylogeny, Eriocaulaceae, Magnoliopsida
- Abstract
Background and Aims: Floral developmental studies are crucial for understanding the evolution of floral structures and sexual systems in angiosperms. Within the monocot order Poales, both subfamilies of Eriocaulaceae have unisexual flowers bearing unusual nectaries. Few previous studies have investigated floral development in subfamily Eriocauloideae, which includes the large, diverse and widespread genus Eriocaulon. To understand floral variation and the evolution of the androecium, gynoecium and floral nectaries of Eriocaulaceae, we analysed floral development and vasculature in Eriocaulon and compared it with that of subfamily Paepalanthoideae and the related family Xyridaceae in a phylogenetic context., Methods: Thirteen species of Eriocaulon were studied. Developmental analysis was carried out using scanning electron microscopy, and vasculature analysis was carried out using light microscopy. Fresh material was also analysed using scanning electron microscopy with a cryo function. Character evolution was reconstructed over well-resolved phylogenies., Key Results: Perianth reductions can occur due to delayed development that can also result in loss of the vascular bundles of the median sepals. Nectariferous petal glands cease development and remain vestigial in some species. In staminate flowers, the inner stamens can emerge before the outer ones, and carpels are transformed into nectariferous carpellodes. In pistillate flowers, stamens are reduced to staminodes and the gynoecium has dorsal stigmas., Conclusions: Floral morphology is highly diverse in Eriocaulon, as a result of fusion, reduction or loss of perianth parts. The nectariferous carpellodes of staminate flowers originated first in the ancestor of Eriocaulaceae; petal glands and nectariferous branches of pistillate flowers originated independently in Eriocaulaceae through transfer of function. We present a hypothesis of floral evolution for the family, illustrating a shift from bisexuality to unisexuality and the evolution of nectaries in a complex monocot family, which can contribute to future studies on reproductive biology and floral evolution in other groups., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2021
- Full Text
- View/download PDF
8. Inside-out flowers of Lacandonia brasiliana (Triuridaceae) provide new insights into fundamental aspects of floral patterning.
- Author
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Rudall PJ, Alves M, and Sajo Md
- Abstract
Background and Aims. A recently described Brazilian species, Lacandonia brasiliana, shares with its longer established putative sister species from Mexico, L. schismatica, inverted floral patterning (carpels surrounding stamens) that is almost unique among angiosperms. We present a detailed ontogenetic study of L. brasiliana for comparison with other members of the tribe Triurideae (Triuridaceae) to explore the possible evolutionary origins of "inside-out" flowers. Methods. Wild-source populations of L. brasiliana were compared morphologically and ontogenetically with related species of Triurideae, using light and scanning electron microscopy. Key Results. Relatively few morphological differences separate flowers of L. brasiliana and L. schismatica. Both species have tepals with late-developing subapical appendages. In both species, the three central (almost sessile) anthers develop precociously with respect to the carpels; the anthers remain closed, and fertilization is achieved via pollen-tube growth from germinating pollen grains of the same cleistogamous flower. Carpels are initiated on fascicles. Conclusions. The close similarity between the two Lacandonia species makes it unlikely that they arose independently from two separate homeotic transformation events; they could either represent sister species or two populations of a single disjunct species. Our study underlines the problematic generic and species boundaries within Triurideae. We present an evolutionary scenario of character evolution in Triuridaceae. The inside-out Lacandonia flower could have resulted from a stabilized homeotic transformation; this hypothesis is not in conflict with constrasting theories of the origin of the Triuridaceae flower, which coincided with a shift to unisexuality. The unisexual yet highly plastic flowers that are typical of Triuridaceae could have pre-adapted the origin of the extraordinary Lacandonia morphology.
- Published
- 2016
- Full Text
- View/download PDF
9. Radicular anatomy of twelve representatives of the Catasetinae subtribe (Orchidaceae: Cymbidieae).
- Author
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Pedroso-de-Moraes C, Souza-Leal Td, Brescansin RL, Pettini-Benelli A, and Sajo Md
- Subjects
- Brazil, Orchidaceae anatomy & histology, Orchidaceae classification, Plant Roots anatomy & histology
- Abstract
Considering that the root structure of the Brazilian genera belonging to the Catasetinae subtribe is poorly known, we describe the roots of twelve representatives from this subtribe. For anatomical analysis, the roots were fixed in FAA 50, preserved in ethanol 70% and sectioned at its medium region using razor blades. The sections were stained with 0.05% astra blue and safranin and mounted in glycerin. For the identification of starch we used Lugol's solution; for lignin, floroglucin chloridric; for lipids, Sudan III, and for flavanoids, potassium hydroxide. The relevant aspects were registered using a digital camera joined with an Olympus microspope (BX51 model). The structural similarities of all roots support the placement of the subtribe Catasetinae into the monophyletic tribe Cymbidieae. Some root features are restricted to one or two taxa and can be useful in the systematics of the subtribe. For example, the occurrence of flavonoidic crystals characterizes the genera Catasetum and Cychnodes, and the number of the velamen layers and the shape of the epivelamen cells are useful to confirm the taxonomic position of Clowesia amazonica. The presence of velamen and flavonoidic crystals was interpreted as an adaptation to the epiphytic habit.
- Published
- 2012
- Full Text
- View/download PDF
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