The Experts below are selected from a list of 1479 Experts worldwide ranked by ideXlab platform
N. Kamdem - One of the best experts on this subject based on the ideXlab platform.
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Spatio-temporal patterns of orchids flowering in Cameroonian rainforests
International Journal of Biometeorology, 2018Co-Authors: N. Texier, V. Deblauwe, T. Stévart, B. Sonké, M. Simo-droissart, L. Azandi, R. Bose, M.-n. Djuikouo, G. Kamdem, N. KamdemAbstract:We characterized the flowering patterns of 45 epiphytic orchid species occurring in Cameroonian rainforests to explore the environmental and evolutionary forces driving their phenology. We used a dataset of 3470 flowering events recorded over a period of 11 years in the Yaoundé living collection (82% of the flowering events) and from in situ observations (18% of the flowering events) to (i) describe flowering frequency and timing and synchronization among taxa; (ii) test flowering patterns for phylogenetic relatedness at the generic level; and (iii) investigate the spatial patterns of phenology. An annual flowering pattern prevailed among the species selected for this study. The species-rich African genera Angraecum and Polystachya are characterized by subannual and annual frequency patterns, respectively. However, in terms of flowering time, no phylogenetic signal was detected for the four most diverse genera ( Ancistrorhynchus , Angraecum , Bulbophyllum , and Polystachya ). Results suggest also an important role of photoperiod and precipitation as climatic triggers of flowering patterns. Moreover, 16% of the taxa cultivated ex situ , mostly Polystachya, showed significant differences in flowering time between individuals originating from distinct climatic regions, pointing toward the existence of phenological ecotypes. Phenological plasticity, suggested by the lack of synchronized flowering in spatially disjunct populations of Polystachya , could explain the widespread radiation of this genus throughout tropical Africa. Our study highlights the need to take the spatial pattern of flowering time into account when interpreting phylogeographic patterns in central African rainforests.
N. Texier - One of the best experts on this subject based on the ideXlab platform.
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Spatio-temporal patterns of orchids flowering in Cameroonian rainforests
International Journal of Biometeorology, 2018Co-Authors: N. Texier, V. Deblauwe, T. Stévart, B. Sonké, M. Simo-droissart, L. Azandi, R. Bose, M.-n. Djuikouo, G. Kamdem, N. KamdemAbstract:We characterized the flowering patterns of 45 epiphytic orchid species occurring in Cameroonian rainforests to explore the environmental and evolutionary forces driving their phenology. We used a dataset of 3470 flowering events recorded over a period of 11 years in the Yaoundé living collection (82% of the flowering events) and from in situ observations (18% of the flowering events) to (i) describe flowering frequency and timing and synchronization among taxa; (ii) test flowering patterns for phylogenetic relatedness at the generic level; and (iii) investigate the spatial patterns of phenology. An annual flowering pattern prevailed among the species selected for this study. The species-rich African genera Angraecum and Polystachya are characterized by subannual and annual frequency patterns, respectively. However, in terms of flowering time, no phylogenetic signal was detected for the four most diverse genera ( Ancistrorhynchus , Angraecum , Bulbophyllum , and Polystachya ). Results suggest also an important role of photoperiod and precipitation as climatic triggers of flowering patterns. Moreover, 16% of the taxa cultivated ex situ , mostly Polystachya, showed significant differences in flowering time between individuals originating from distinct climatic regions, pointing toward the existence of phenological ecotypes. Phenological plasticity, suggested by the lack of synchronized flowering in spatially disjunct populations of Polystachya , could explain the widespread radiation of this genus throughout tropical Africa. Our study highlights the need to take the spatial pattern of flowering time into account when interpreting phylogeographic patterns in central African rainforests.
Kamdem N. - One of the best experts on this subject based on the ideXlab platform.
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Spatio-temporal patterns of orchids flowering in Cameroonian rainforests
2018Co-Authors: Texier N., Stévart B., Sonké B., Simo-droissart M., Azandi L., Bose R., Djuikouo K. M.n., Kamdem G., Kamdem N.Abstract:We characterized the flowering patterns of 45 epiphytic orchid species occurring in Cameroonian rainforests to explore the environmental and evolutionary forces driving their phenology. We used a dataset of 3470 flowering events recorded over a period of 11 years in the Yaoundé living collection (82% of the flowering events) and from in situ observations (18% of the flowering events) to (i) describe flowering frequency and timing and synchronization among taxa; (ii) test flowering patterns for phylogenetic relatedness at the generic level; and (iii) investigate the spatial patterns of phenology. An annual flowering pattern prevailed among the species selected for this study. The species-rich African genera Angraecum and Polystachya are characterized by subannual and annual frequency patterns, respectively. However, in terms of flowering time, no phylogenetic signal was detected for the four most diverse genera (Ancistrorhynchus, Angraecum, Bulbophyllum, and Polystachya). Results suggest also an important role of photoperiod and precipitation as climatic triggers of flowering patterns. Moreover, 16% of the taxa cultivated ex situ, mostly Polystachya, showed significant differences in flowering time between individuals originating from distinct climatic regions, pointing toward the existence of phenological ecotypes. Phenological plasticity, suggested by the lack of synchronized flowering in spatially disjunct populations of Polystachya, could explain the widespread radiation of this genus throughout tropical Africa. Our study highlights the need to take the spatial pattern of flowering time into account when interpreting phylogeographic patterns in central African rainforests.Peer Revie
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Spatio-temporal patterns of orchids flowering in Cameroonian rainforests
'Springer Science and Business Media LLC', 2018Co-Authors: Texier N., Sonké B., Simo-droissart M., Azandi L., Kamdem G., Stévart T., Bose Ruksan, Djuikouo N., Kamdem N.Abstract:International audienceWe characterized the flowering patterns of 45 epiphytic orchid species occurring in Cameroonian rainforests to explore the environmental and evolutionary forces driving their phenology. We used a dataset of 3470 flowering events recorded over a period of 11 years in the Yaoundé living collection (82% of the flowering events) and from in situ observations (18% of the flowering events) to (i) describe flowering frequency and timing and synchronization among taxa; (ii) test flowering patterns for phylogenetic relatedness at the generic level; and (iii) investigate the spatial patterns of phenology. An annual flowering pattern prevailed among the species selected for this study. The species-rich African genera Angraecum and Polystachya are characterized by subannual and annual frequency patterns, respectively. However, in terms of flowering time, no phylogenetic signal was detected for the four most diverse genera (Ancistrorhynchus, Angraecum, Bulbophyllum, and Polystachya). Results suggest also an important role of photoperiod and precipitation as climatic triggers of flowering patterns. Moreover, 16% of the taxa cultivated ex situ, mostly Polystachya, showed significant differences in flowering time between individuals originating from distinct climatic regions, pointing toward the existence of phenological ecotypes. Phenological plasticity, suggested by the lack of synchronized flowering in spatially disjunct populations of Polystachya, could explain the widespread radiation of this genus throughout tropical Africa. Our study highlights the need to take the spatial pattern of flowering time into account when interpreting phylogeographic patterns in central African rainforest
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Spatio-temporal patterns of orchids flowering in Cameroonian rainforests
2018Co-Authors: Texier Nicolas, Sonké B., Simo-droissart M., Azandi L., Bose R., Kamdem G., Stévart T., Deblauwe Vincent, Djuikouo M. N., Kamdem N.Abstract:We characterized the flowering patterns of 45 epiphytic orchid species occurring in Cameroonian rainforests to explore the environmental and evolutionary forces driving their phenology. We used a dataset of 3470 flowering events recorded over a period of 11 years in the Yaounde living collection (82% of the flowering events) and from in situ observations (18% of the flowering events) to (i) describe flowering frequency and timing and synchronization among taxa; (ii) test flowering patterns for phylogenetic relatedness at the generic level; and (iii) investigate the spatial patterns of phenology. An annual flowering pattern prevailed among the species selected for this study. The species-rich African genera Angraecum and Polystachya are characterized by subannual and annual frequency patterns, respectively. However, in terms of flowering time, no phylogenetic signal was detected for the four most diverse genera (Ancistrorhynchus, Angraecum, Bulbophyllum, and Polystachya). Results suggest also an important role of photoperiod and precipitation as climatic triggers of flowering patterns. Moreover, 16% of the taxa cultivated ex situ, mostly Polystachya, showed significant differences in flowering time between individuals originating from distinct climatic regions, pointing toward the existence of phenological ecotypes. Phenological plasticity, suggested by the lack of synchronized flowering in spatially disjunct populations of Polystachya, could explain the widespread radiation of this genus throughout tropical Africa. Our study highlights the need to take the spatial pattern of flowering time into account when interpreting phylogeographic patterns in central African rainforests
Tariq Stevart - One of the best experts on this subject based on the ideXlab platform.
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Polystachya orophila (Orchidaceae, Polystachynae), a new species from tropical West Africa, and clarification on the nomenclature and taxonomy of P. microbambusa
Phytotaxa, 2016Co-Authors: Ehoarn Bidault, Porter P. Lowry, Tariq StevartAbstract:Polystachya orophila , a new species of Orchidaceae, is described based on specimens collected during the baseline study of the Guinean Nimba Mountains for the environmental impact assessment for a proposed mining project. While material belonging to this species was mentioned as early as 1920 by Chevalier, it has historically been confused with P. microbambusa , from which it differs by its typically Polystachya -like clustered pseudobulbs, placing it in P. sect. Polystachya , whereas P. microbambusa has pseudobulbs successively growing on top of one another, forming developed and persistent stems, and is the sole representative of P. sect . Dimorphocaules . The complex taxonomic and nomenclatural history of P. microbambusa is also clarified. For both taxa we provide a morphological description as well as information on distribution, habitat, and phenology, an IUCN conservation status assessment using the Red List criteria, and a distribution map, along with a dichotomous key that also includes the most similar members of P. sect. Polystachya.
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deux especes nouvelles de Polystachya orchidaceae de guinee equatoriale
Adansonia, 2007Co-Authors: Tariq Stevart, Ingrid Parmentier, Vincent DroissartAbstract:Two new species of Polystachya (Orchidaceae) from Equatorial Guinea. Polystachya reticulata Stevart & Droissart and P. engongensis Stevart & Droissart, two new species of orchids from Rio Muni and Bioko (Equatorial Guinea), are described and illustrated. Polystachya reticulata diff ers from others Polystachya section Affi nes by an entire lip. Polystachya engongensis closey resembles P. ramulosa Lindl. by its lip shape, but diff ers by its habit.
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trois especes et trois combinaisons nouvelles de Polystachya orchidaceae du cameroun de guinee equatoriale et du gabon
Adansonia, 2004Co-Authors: Tariq Stevart, Norberto N NguemaAbstract:Trois Orchidaceae nouvelles du Rio Muni (Guinee Equatoriale) et du Gabon sont decrites et illustrees : Polystachya bipoda Stevart, P. lejolyana Stevart et P. riomuniensis Stevart & Nguema. Trois nouvelles combinaisons sont proposees: Polystachya albescens Ridl. subsp. polyphylla (Summerh.) Stevart, P. odorata Lindl. subsp. gabonensis (Summerh.) Stevart et P. odorata Lindl. subsp. trilepidis (summerh.) Stevart.
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a new species of Polystachya sect polychaete orchidaceae from central africa
Bulletin du Jardin Botanique National de Belgique, 2003Co-Authors: Tariq Stevart, Ingrid Parmentier, Daniel Geerinck, Jean LejolyAbstract:A new species of Polystachya Hook.f. sect. Polychaete Cribb (Orchidaceae) is described from Sao Tome, Gabon and Rio Muni (Equatorial Guinea): Polystachya moniquetiana Stevart & Geerinck. It is related to Polystachya polychaete Kraenzl. from which it differs in the lip and plant size.
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quatre nouveaux taxons d orchidaceae des genres liparis bulbophyllum Polystachya et calanthe decouverts a sao tome et principe
Bulletin du Jardin Botanique National de Belgique, 2000Co-Authors: Tariq Stevart, Daniel GeerinckAbstract:Four new taxa of Orchidaceae in the genera Liparis, Bulbophyllum, Polystachya and Calanthe discovered from Slio Tome and Principe. Four new taxa of Orchidaceae are described from Sio Tomd : Liparis rosseelii Stivart (two collections), Bulbophyllum luciphilum Stdvart (based one collection), Polystachya albescens subsp. principensis Stdvart (sect. Caulescentes; based on ten collections) and Calanthe sylvatica var. geerinckiana Stivart (based on one collection).
Alfredo Ortega - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of the antiprotozoal activity of neo-clerodane type diterpenes from Salvia Polystachya against Entamoeba histolytica and Giardia lamblia.
Phytotherapy Research, 2009Co-Authors: Fernando Calzada, Elihu Bautista, Lilian Yépez-mulia, Amparo Tapia-contreras, Emma Maldonado, Alfredo OrtegaAbstract:Chia (Salvia Polystachya Ort., Lamiaceae) is frequently used in Mexican traditional medicine to treat dysentery. In this study the main neo-clerodane diterpenes (polystachynes A, B and D, as well as linearolactone) were isolated from the aerial parts of chia, and their antiprotozoal activities toward Entamoebahistolytica and Giardia lamblia trophozoites were evaluated in vitro. Linearolactone was the most potent antiamoebic and antigiardial compound with IC50 values of 22.9 μM for E. histolytica and 28.2 μM for G. lamblia. Polystachynes A, B and D, showed moderate antiprotozoal activity against both protozoans with IC50 values ranging from 117.0 to 160.6 μM for E. histolytica and from 107.5 to 134.7 μM for G. lamblia. These data suggest that linearolactone may play an important role in the antidiarrhoeal activity of S. Polystachya. Copyright © 2009 John Wiley & Sons, Ltd.
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Polystachyne F, a 5,10- seco -Neoclerodane from Salvia Polystachya
CHEMICAL & PHARMACEUTICAL BULLETIN, 2006Co-Authors: Alfredo Ortega, Elihu Bautista, Emma MaldonadoAbstract:A new 5,10-seco-neoclerodane diterpene, polystachyne F (1), was isolated from the aerial parts of Salvia Polystachya. Its structure was established on the basis of its spectroscopic properties and X-ray crystallographic analysis. Some correlations in the NOESY spectrum of 1 suggested the existence of a conformational equilibrium.
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Polystachynes A–E, five cis -neo-clerodane diterpenoids from Salvia Polystachya
Phytochemistry, 2000Co-Authors: Emma Maldonado, Alfredo OrtegaAbstract:From the aerial parts of Salvia Polystachya five new neo-clerodane diterpenoids, polystachynes A-E, have been isolated. The structures were established by spectroscopic methods, including the X-ray analysis of polystachynes C and D. The known clerodanes salvifaricin, linearolactone and dehydrokerlin were also isolated.
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polystachynes a e five cis neo clerodane diterpenoids from salvia Polystachya
Phytochemistry, 2000Co-Authors: Emma Maldonado, Alfredo OrtegaAbstract:From the aerial parts of Salvia Polystachya five new neo-clerodane diterpenoids, polystachynes A-E, have been isolated. The structures were established by spectroscopic methods, including the X-ray analysis of polystachynes C and D. The known clerodanes salvifaricin, linearolactone and dehydrokerlin were also isolated.