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184 results on '"Singer, Rodrigo B."'

2. Determination of amino acid content, fatty acid profiles, and phenolic compounds in non-conventional edible fruits of seven species of palm trees (Arecaceae) native to the southern half of South America

Author

Rodrigues, Carlos Eduardo, Schäfer, Laura, Gregolon, Jean Guilherme Novello, de Oliveira, Julia Ferreira, Baez, Oscar Perdomo, Deolindo, Carolina Turnes Pasini, de Melo, Ana Paula Zapelini, Singer, Rodrigo B., Ledur Kist, Tarso B., and Hoff, Rodrigo

Published
2022
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35. Dating the origin of the Orchidaceae from a fossil orchid with its pollinator

Author

Ramirez, Santiago R., Gravendeel, Barbara, Singer, Rodrigo B., Marshall, Charles R., and Pierce, Naomi E.

Subjects
Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Author(s): Santiago R. Ramírez (corresponding author) [1]; Barbara Gravendeel [2]; Rodrigo B. Singer [3]; Charles R. Marshall [1, 4]; Naomi E. Pierce [1] Since the time of Darwin [1], evolutionary [...]

Published
2007
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39. Looking for non-hermaphrodite cacti: multidisciplinary studies in Gymnocalycium bruchiiendemic to central Argentina

Author

Delbón, Natalia E., Aliscioni, Nayla L., Lorenzati, Marina, García, Sergio, Singer, Rodrigo B., and Gurvich, Diego E.

Abstract

Key message: Through a multidisciplinary study we found that Gymnocalycium bruchii, an endemic cactus from central Argentina, acts as a dioecious species, which is the first record in this genus. Abstract: Cactaceae species are typically hermaphroditic; however, about 2% have other different reproductive systems. These non-hermaphroditic species may develop sexual dimorphism in flowers or other reproductive, vegetative or ecological traits, besides a specific breeding system and floral ontogeny. Therefore, multidisciplinary research is necessary to fully understand reproduction in those species. For this purpose, we studied Gymnocalicium bruchii, a globose cactus endemic to central Argentina that is presumably dioecious or gynodioecious. We made observations in two natural and two cultivated populations. We made morphological observations of plants and flowers, and performed quantitative analyses to determine the sex ratio, size of plants and flowers, flower production, fruiting, among other variables. We performed hand-pollination, self-fertilization and free-pollination tests to determine the breeding system. Finally, we studied the anatomy and ontogeny of the reproductive organs using permanent histological slides of flower morphs at different stages. Our results confirm that Gymnocalicium bruchiiis a dioecious species. Female flowers have atrophied anthers and a functional gynoecium that produces fruits and seeds. Male flowers are bigger and have a functional androecium but a sterile gynoecium. In the cultivated population, the sex ratio was 1/1, whereas the number of male individuals was higher in both natural populations. Pollination tests corroborated dioecy. Ontogenetic studies revealed that in female flowers the anthers collapse before microspore maturation, while in male flowers the gynoecium shows normal development of the ovary, style, stigma, and ovules; however, the latter are never fertilized.

Published
2023
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42. Pollination biology and reproductive success in four Brazilian species of Gomesa (Orchidaceae: Oncidiinae): Specific pollinators, but high pollen loss and low fruit set.

Author

Castro, Jonas B., Perdomo, Oscar, and Singer, Rodrigo B.

Subjects
POLLINATION, BIOLOGICAL fitness, POLLEN, POLLINATORS, SPECIES, BIOLOGY
Abstract

Four species of Gomesa (Gomesa flexuosa, Gomesa ranifera, Gomesa cornigera, and Gomesa riograndensis), a horticulturally important, albeit scarcely studied orchid genus, were investigated. Pollination biology was studied through fieldwork in Rio Grande do Sul in Southern Brazil during two flowering seasons. Breeding systems were studied through controlled pollinations in cultivated plants. All studied species secrete floral oils through elaiophores and are exclusively pollinated by native, oil‐collecting bees of the Centridini or Tapinotaspidini tribes. Pollinarium reconfiguration after withdrawal, a feature likely promoting cross‐pollination, was recorded in G. cornigera and G. riograndensis. All studied species are pollinator‐dependent and either predominantly or fully self‐incompatible, that is, unable to set fruit following self‐pollination. The used indexes of pollination efficiency consistently scored values below 1, indicating that in all studied species less than one flower is pollinated per pollinarium removed. Accordingly, pollen loss was high, ranging from 40% to 75%. Furthermore, inflorescences in natural populations displayed low fruit sets (below 13%). Gomesa flexuosa presented the highest values of pollinarium removal (36.24%) and deposition (15.34%). Significantly, this is the only studied species bearing a tabula infraestigmatica, a column swelling that bees hold to stabilize themselves while gathering the floral oils. Since pollinators were observed in all studied species spending considerable time (up to 3 min 46 s) and visiting several (up to 19) flowers, we propose that the observed low fruit set is the result of a combination of self‐incompatibility, pollinator‐mediated self‐pollination, and pollen loss. [ABSTRACT FROM AUTHOR]

Published
2022
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45. Phylogenetic systematics of subtribe Spiranthinae (Orchidaceae: Orchidoideae: Cranichideae) based on nuclear and plastid DNA sequences of a nearly complete generic sample

Author

Salazar, Gerardo A, primary, Batista, João A N, additional, Cabrera, Lidia I, additional, van Den Berg, Cássio, additional, Whitten, W Mark, additional, Smidt, Eric C, additional, Buzatto, Cristiano Roberto, additional, Singer, Rodrigo B, additional, Gerlach, Günter, additional, Jiménez-Machorro, Rolando, additional, Radins, José A, additional, Insaurralde, Irma S, additional, Guimarães, Leonardo R S, additional, de Barros, Fábio, additional, Tobar, Francisco, additional, Linares, José L, additional, Mújica, Ernesto, additional, Dressler, Robert L, additional, Blanco, Mario A, additional, Hágsater, Eric, additional, and Chase, Mark W, additional

Published
2018
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49. Zygostates dasyrhiza (Kraenzl.) Schltr. (Orchidaceae: Oncidiinae), a new record from Rio Grande do Sul, Brazil

Author

Buzatto, Cristiano Roberto and Singer, Rodrigo B.

Subjects
Oncidiinae, Orchidaceae, taxonomia, distribuição geográfica, Região Sul, Botânica, taxonomy, geographic distribution, Southern Brazil
Abstract

Zygostates dasyrhiza (Kraenzl.) Schltr. is here documented for the first time for the state of Rio Grande do Sul, Brazil. A morphological description, data about geographic distribution and habitat, an artificial key to the three Zygostates species native to Rio Grande do Sul, and additional comments about this species are provided., (Zygostates dasyrhiza (Kraenzl.) Schltr. (Orchidaceae: Oncidiinae), novo registro para o Rio Grande do Sul, Brasil) A presença de Zygostates dasyrhiza (Kraenzl.) Schltr. (Orchidaceae: Oncidiinae) é documentada pela primeira vez para o estado do Rio Grande do Sul. Neste trabalho são apresentados a descrição, distribuição geográfica, hábitat e comentários adicionais para a espécie, bem como uma chave artificial para separar as três espécies de Zygostates nativas do Rio Grande do Sul.

Published
2011

50. O gênero Cattleya Lindl. (Orchidaceae: Laeliinae) no Rio Grande do Sul, Brasil

Author

Buzatto, Cristiano Roberto, Ferreira, Priscila Porto Alegre, Welker, Cassiano Aimberê Dorneles, Seger, Guilherme Dubal dos Santos, Hertzog, Anelise, and Singer, Rodrigo B.

Subjects
Botânica, Cattleya, Orchidaceae, Laeliinae, taxonomia, flora do Rio Grande do Sul, taxonomy, flora of Rio Grande do Sul State
Abstract

Cattleya presents about 120 species distributed in tropical and subtropical regions of the Americas. In its current delimitation, Cattleya also encompasses the Brazilian species formerly placed within the genera Laelia and Sophronitis, as well as the species of a number of recently segregated genera. This contribution deals with this genus in Rio Grande do Sul State, Southern Brazil, therefore contributing to the knowledge of its orchid flora. This work is based in literature and in the analysis of herbarium vouchers as well as in specimens collected during fieldwork in several localities of Rio Grande do Sul. Five native species were recorded: Cattleya cernua, C. coccinea, C. intermedia, C. purpurata and C. tigrina. All these species dwell within the Atlantic Rain Forest biome. This contribution does present an artificial key for the species, the synonymies, descriptions, illustrations, geographic distribution and comments on habitat and natural history of the species., Cattleya abrange aproximadamente 120 espécies distribuídas principalmente nas regiões tropicais e subtropicais das Américas. Em sua delimitação atual, Cattleya inclui também as espécies brasileiras outrora inseridas nos gêneros Laelia e Sophronitis, bem como as espécies de gêneros mais recentemente segregados. O presente trabalho trata do estudo taxonômico desse gênero no Rio Grande do Sul, contribuindo, portanto, para o conhecimento da flora do estado. Este trabalho baseou-se em revisão bibliográfica bem como na análise de espécimes de herbário e coletas efetuadas em diversas regiões do Rio Grande do Sul. Cinco espécies ocorrem no estado: Cattleya cernua, C. coccinea, C. intermedia, C. purpurata e C. tigrina. Todas essas espécies crescem em formações florestais inseridas no bioma Mata Atlântica. Este trabalho apresenta uma chave artificial para identificar as espécies, sinonímias, descrições, ilustrações, distribuição geográfica, hábitat e comentários adicionais dos táxons analisados.

Published
2010

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