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| Registros recuperados: 16 | |
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| Rabaey, D.; Lens, F.; Huysmans, S.; Smets, E.; Jansen, S.. |
| Recent micromorphological observations of angiosperm pit membranes have extended the number and range of taxa with pseudo-tori in tracheary elements. This study investigates at ultrastructural level (TEM) the development of pseudo-tori in the unrelated Malus yunnanensis, Ligustrum vulgare, Pittosporum tenuifolium, and Vaccinium myrtillus in order to determine whether these plasmodesmata associated thickenings have a similar developmental pattern across flowering plants. At early ontogenetic stages, the formation of a primary thickening was observed, resulting from swelling of the pit membrane in fibre-tracheids and vesselelements. Since plasmodesmata appear to be frequently, but not always, associated with these primary pit membrane thickenings, it remains... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Ontogeny; Pseudo-torus; Tracheary element; Pit membrane; Bordered pit; Wood ultrastructure; 42.56. |
| Ano: 2008 |
URL: http://www.repository.naturalis.nl/record/430078 |
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| Wilkin, P.; Schols, P.; Chase, M.; Chayamarit, K.; Furness, C.; Huysmans, S.; Rakotonasolo, F.; Smets, E.; Thapyai, C.. |
| Following recent phylogenetic studies of the families and genera of Dioscoreales, the identification of monophyletic infrageneric taxa in the pantropical genus Dioscorea is a priority. A phylogenetic analysis based on sequence data from the plastid genes rbcL and matK is presented, using 67 species of Dioscorea and covering all the main Old World and selected New World lineages. The analysis used 14 outgroup taxa, including Trichopus Gaertn., Tacca J.R. & G. Forster, Stenomeris Planch., Burmannia L. and Thismia Griff. The main findings are: a) that a clade of rhizomatous taxa is sister to the rest of Dioscorea; b) the main Old World groups (such as the right-twining D. sect. Enantiophyllum) are monophyletic and c) there are two distinct lineages among... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Dioscorea; Phylogeny; Classification; Analysis; Plastid genes; RbcL; MatK; Character evolution. |
| Ano: 2005 |
URL: http://www.repository.naturalis.nl/record/407311 |
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| Moon, H.-K.; Vinckier, S.; Walker, J.; Smets, E.F.; Huysmans, S.. |
| The pollen morphology and ultrastructure of the subtribe Salviinae were investigated with light, scanning electron, and transmission electron microscopy. In addition, cladistic analyses of the obtained morphological data, supplemented with rbcL data from GenBank, were conducted in order to assess the phylogenetic signal of palynological characters. Salviinae pollen is small to large, oblate to prolate in shape, with a circular to slightly elliptic amb, and mostly hexacolpate. Perovskia abrotanoides appears to be distylous and shows a significant pollen dimorphism between pin and thrum flowers. The sexine ornamentation of the genera Lepechinia and Chaunostoma is perforate, while the ornamentation of other genera is bireticulate. Perovskia expresses a unique... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Pollen morphology Salviinae sexine ornamentation symplesiomorphic condition improved resolution bootstrap support values molecular phylogenetic analyses ultrastructure 42.41; 42.58. |
| Ano: 2008 |
URL: http://www.repository.naturalis.nl/record/449556 |
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| Huysmans, S.; Robbrecht, E.; Smets, E.. |
| Recent literature is controversial as regards the segregation of Hallea and Mitragyna, and pretends that the two genera show pollen morphological differences. In the present study the pollen morphology of all ten species of the complex is described on the basis of light and scanning electron microscopy (including examination of broken grains, which were obtained with a technique never applied in palynology, viz. shaking with glass beads). The two genera have 3-zonocolporate grains with compound apertures (endoapertures are always H-shaped, sometimes incompletely so). While Hallea showed to be stenopalynous (sexine always tectate-perforate), Mitragyna is more variable (sexine microreticulate or tectate-perforate), and several of its species have pollen... |
| Tipo: Article / Letter to the editor |
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| Ano: 1994 |
URL: http://www.repository.naturalis.nl/record/524503 |
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| Moon, H.-K.; Vinckier, S.; Smets, E.F.; Huysmans, S.. |
| This study provides new pollen data of 52 representative species belonging to all 12 genera in the currently classification of the subtribe Nepetinae, and considers the possible presence of orbicules for the first time. Pollenmorphology and ultrastructure were investigated with light, scanning electron and transmission electron microscopy. Nepetinaepollen is small to large (P = 16–65 µm, E = 17–53 µm), oblate to prolate (P/E = 0.7–1.6) in shape and mostly hexacolpate (sometimes octocolpate). The exine stratification in all taxa studied is similar and characterized by unbranched columellae and a continuous, granular endexine. Sexine ornamentation in the Nepetinae is bireticulate, microreticulate or perforate. In perforate and microreticulate pattern a... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Nepetoidea orbicules palynology Nepetinae sexine ornamentation ultrastructure 42.41; 42.48; 42.58. |
| Ano: 2008 |
URL: http://www.repository.naturalis.nl/record/449553 |
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| Jacobs, B.; Donoghue, M.J.; Bouman, F.; Huysmans, S.; Smets, E.F.. |
| Recent phylogenetic analyses based on molecular markers have resulted in a solid phylogeny of Viburnum with 12 well-defined clades. This has allowed us to focus on character evolution, endocarp and seed characters in particular. Members of Viburnum bear drupes that differ considerably between clades. Characters such as pyrene shape and grooving, number of fibrous layers, seed coat anatomy, and seed rumination are phylogenetically highly valuable. Our results largely agree with the results based on molecular data and provide several additional insights. The position of V. clemensae as sister to the rest of Viburnum is supported by several characters. The early diversification of V. clemensae might explain its highly derived features. Furthermore, our... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Viburnum Adoxaceae endocarp seed evolution phylogeny 42.43; 42.58. |
| Ano: 2008 |
URL: http://www.repository.naturalis.nl/record/449561 |
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| Groeninckx, I.; Vrijdaghs, A.; Huysmans, S.; Smets, E.; Dessein, S.. |
| Background and Aims Members of Rubiaceae are generally characterized by an inferior ovary. However, Mitrasacmopsis is cited in the literature as having a semi-inferior to superior ovary. It has previously been hypothesized that the gynoecial development of Rubiaceae with semi-inferior to superior ovaries takes place in the same way as in Gaertnera, one of the most commonly cited rubiaceous genera with a superior ovary. To test this hypothesis, a floral ontogenetic study of Mitrasacmopsis was carried out with special attention paid to the gynoecial development. Methods Floral ontogeny and anatomy of Mitrasacmopsis were examined using scanning electron and light microscopy. Key Results At an early developmental stage, a concavity becomes visible in the... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Mitrasacmopsis quadrivalvis; Gaertnera; Floral ontogeny; 42.48. |
| Ano: 2007 |
URL: http://www.repository.naturalis.nl/record/422222 |
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| Verellen, J.; Dessein, S.; Razafimandimbison, S.G.; Smets, E.; Huysmans, S.. |
| The tribe Naucleeae has recently been recircumscribed on the basis of both morphological and molecular [rbcL, trnT-F, internal transcribed spacer (ITS)] evidence, and has been found to be the sister group of the tribe Hymenodictyeae Razafim. & B. Bremer. In order to find pollen morphological support for this new classification, the pollen and orbicules of 65 species, representing 23 Naucleeae and the two Hymenodictyeae genera, were investigated by scanning electron and light microscopy. Naucleeae pollen is very small (< 20 µm) to small (20–30 µm) and its shape in equatorial view is suboblate to spheroidal or, more rarely, subprolate. Three compound apertures are present, each comprising a long and narrow ectocolpus, a circular to slightly lolongate... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Compound apertures; Endoapertures; Orbicule morphology; Palynology; Sexine ornamentation; 42.48. |
| Ano: 2007 |
URL: http://www.repository.naturalis.nl/record/422226 |
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| Rabaey, D.; Huysmans, S.; Lens, F.; Smets, E.; Jansen, S.. |
| Recent studies on the functional significance of pit membranes in water conducting cells have renewed general interest in their micromorphology. At least two types of pit membrane thickenings have been described in angiosperm families, i.e. genuine tori and pseudo-tori. This study explores the distribution and morphology of pit membrane thickenings in 69 species and 23 genera within Oleaceae using light and electron microscopy. Torus-bearing pit membranes are confirmed for Osmanthus, and new records are reported for Chionanthus retusa, Picconia azorica, and P. excelsa, but not for the other species studied of Chionanthus. This infrageneric variation suggests that tori represent a plastic feature that has evolved more than once within the family as the... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Electron microscopy; Pit aperture; Pit membrane; Plasmodesmata; Pseudo-torus; Torus; Tracheid; Vessel element; 42.56. |
| Ano: 2008 |
URL: http://www.repository.naturalis.nl/record/429536 |
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| Dessein, S.; Ochoterena, H.; De Block, P.; Lens, F.; Robbrecht, E.; Schols, P.; Smets, E.; Vinckier, S.; Huysmans, S.. |
| In the 1990s Rubiaceae became a hot spot for systematists, mainly due to the comprehensive treatment of the family by Robbrecht in 1988. Next to the exploration of macromolecular characters to infer the phylogeny, the palynology of Rubiaceae finally received the attention it deserves. This article aims to present a state-of-the-art analysis of the systematic palynology of the family. The range of variation in pollen morphology is wide, and some of the pollen features are not known from other angiosperm taxa; e.g., a looplike or spiral pattern for the position of apertures in pantoaperturate grains. We compiled an online database at the generic level for the major pollen characters and orbicule presence in Rubiaceae. An overview of the variation is... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Rubiaceae; Pollen morphology; Palynology; Phylogeny. |
| Ano: 2005 |
URL: http://www.repository.naturalis.nl/record/407298 |
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| Merckx, V.; Schols, P.; Geuten, K.; Huysmans, S.; Smets, E.F.. |
| Amolecular phylogenetic analysis of Nartheciaceae is presented, with nine species of the family’s five genera. The main phylogenetic findings are: (a) Nietneria and Narthecium are placed in a clade sister to Lophiola; (b) sister to the Lophiola-Narthecium- Nietneria clade is a clade formed by Aletris and the monospecific Metanarthecium; (c) the inclusion of Metanarthecium luteo-viride in Aletris, as proposed by several authors, is well supported. The pollen and orbicule morphology of representatives of five genera is described. The results underline a close relationship between Nietneria, Narthecium, and Lophiola and confirm the previously reported observations of Metanarthecium pollen and the types of sexine ornamentation in Aletris. Pollen grains of... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Dioscoreales Nartheciaceae Nietneria molecular phylogeny orbicules pollen morphology 42.43; 42.48; 42.57. |
| Ano: 2008 |
URL: http://www.repository.naturalis.nl/record/449539 |
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| Schols, P.; Wilkin, P.; Furness, C.; Huysmans, S.; Smets, E.. |
| Pollen character evolution in yams (Dioscorea: Dioscoreaceae) was investigated in relation to the phylogeny obtained from a recent combined analysis of rbcL and matK gene sequences. The following characters were evaluated: pollen size, aperture number, sexine ornamentation, perforation density, and orbicule presence or absence. Continuous characters were coded using the gap weighting method. Each character was optimized using MacClade onto a tree selected at random from analyses based on molecular data of Wilkin et al. The results indicate that in Dioscorea pollen size decreases in the more derived clades. The latter observation may be related to the evolution of annually replaced tubers. Aperture number increases from one in the monosulcate Stenophora... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Dioscorea; Dioscoreaceae; Pollen; Evolution; Phylogeny. |
| Ano: 2005 |
URL: http://www.repository.naturalis.nl/record/407309 |
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| Lens, F.; Jansen, S.; Huysmans, S.; Robbrecht, E.; Smets, E.. |
| The Vanguerieae is a large tribe of the subfamily Ixoroideae (Rubiaceae) and consists of about 500 species in 27 genera. This study gives a detailed pollen morphological description of 30 species from 16 genera, based on light microscopy and scanning electron microscopy. The Vanguerieae are considered to be stenopalynous, although there is some evidence to question this. First, there is a difference in sexine types that clearly de® nes Keetia and Psydrax ( both reticulate) , and Canthium and Vanguerieae (both perforate with very small perforations) from the other Vanguerieae investigated. Second, pollen grains corroborate the subgeneric delimitations of Canthium sensu Bridson. Pollen morphologically the tribe is characterised by ( 1) the shape of the... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Vanguereae; Ixoroideae; Rubiaceae; Pollen; Morphological variation; Stenopalynous; 42.58. |
| Ano: 2000 |
URL: http://www.repository.naturalis.nl/record/423771 |
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| Lens, F.; Kårehed, J.; Baas, P.; Jansen, S.; Rabaey, D.; Huysmans, S.; Hamann, T.; Smets, E.. |
| Wood samples from 53 species belonging to 41 genera of the Icacinaceae s.l. are investigated using light and scanning electron microscopy. The traditionally circumscribed Icacinaceae fall apart into four segregate families that are clearly nested within asterids, i.e., Icacinaceae s.str. (near or in Garryales), Cardiopteridaceae and Stemonuraceae (both Aquifoliales), and Pennantiaceae (Apiales). From a wood anatomical point of view, these families cannot easily be distinguished from each other. However, some features such as vessel distribution, perforation plate morphology, size and arrangement of vessel pits, fibre wall thickness, and the occurrence of cambial variants can be used to assign various species to one of the four families. The wood structure... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Cambial variants; Comparative wood anatomy; Garryales; Icacinaceae; LM; Oncotheca; SEM; 42.58. |
| Ano: 2008 |
URL: http://www.repository.naturalis.nl/record/424648 |
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| Registros recuperados: 16 | |
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