Consulta: creatorFacets:"Lens, F."
Registros recuperados: 41
Data/hora: 10/06/2024 02:30:20

A search for phylogenetically informative wood characters within Lecythidaceae s.l.
Provedor de dados: 16
Autores: Lens, F.; Baas, P.; Jansen, S.; Smets, E.
The wood structure of 71 species representing 24 genera of the pantropical Lecythidaceae s.l., including the edible Brazil nuts (Bertholletia excelsa) and the spectacular cannon-ball tree (Couroupita guianensis), was investigated using light and scanning electron microscopy. This study focused on finding phylogenetically informative characters to help elucidate any obscure evolutionary patterns within the family. The earliest diverging subfamily Napoleonaeoideae has mixed simple/scalariform vessel perforations, scalariform vessel-ray pitting, and high multiseriate rays, all features that are also present in Scytopetaloideae. The wood structure of Napoleonaea is distinct, but its supposed close relative Crateranthus strongly resembles Scytopetaloideae. The...
Tipo: Article / Letter to the editor
Palavras-chave: Ericales; Lecythidaceae s.l.; Lecythidaceae s.s.; Napoleonaeaceae; Scytopetalaceae; Systematic wood anatomy; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/422216

Flowering-time genes modulate meristem determinacy and growth form in Arabidopsis thaliana
Provedor de dados: 16
Autores: Melzer, S.; Lens, F.; Gennen, J.; Vanneste, S.; Rohde , A.; Beeckman, T.
Plants have evolved annual and perennial life forms as alternative strategies to adapt reproduction and survival to environmental constraints. In isolated situations, such as islands, woody perennials have evolved repeatedly from annual ancestors1. Although the molecular basis of the rapid evolution of insular woodiness is unknown, the molecular difference between perennials and annuals might be rather small, and a change between these life strategies might not require major genetic innovations2,3. Developmental regulators can strongly affect evolutionary variation4 and genes involved in meristem transitions are good candidates for a switch in growth habit. We found that the MADS box proteins SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) and FRUITFULL...
Tipo: Article / Letter to the editor
Palavras-chave: Flowering-time; Meristem determinacy; Growth form; Arabidopsis thaliana; Insular woodiness; Secondary growth; Annual life forms; 42.56.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/429531

Comparative wood anatomy of Andromedeae s.s., Gaultherieae, Lyonieae and Oxydendreae (Vaccinioideae, Ericaceae s.l.)
Provedor de dados: 16
Autores: Lens, F.; Smets, E.; Jansen, S.
The wood anatomical structure of 11 out of 13 genera from four tribes of the Vaccinioideae, namely Andromedeae s.s., Gaultherieae, Lyonieae and Oxydendreae (Ericaceae s.l.), is described using light and scanning electron microscopy. Several features of the secondary xylem support the tribal classification based on molecular data: arrangement of vessel-ray pitting, height of multiseriate rays and the shape of the body ray cells. Oxydendreae are clearly defined from the other representatives by various wood anatomical features. Gaultherieae can be distinguished from Lyonieae by differences in vessel perforation plates, vessel-ray pitting, height and structure of multiseriate rays, and occurrence of prismatic crystals, but the wood of Andromedeae s.s. is...
Tipo: Article / Letter to the editor
Palavras-chave: Comparative wood anatomy; Andromedeae; Gaultherieae; Lyonieae; Oxydendreae; Vaccinioideae; Ericaceae; Andromedeae sensu Stevens; Pith structure; 42.58.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/424620

Variation in xylem structure from tropics to tundra: Evidence from vestured pits
Provedor de dados: 16
Autores: Jansen, S.; Baas, P.; Gasson, P.; Lens, F.; Smets, E.
Bordered pits play an important role in permitting water flow among adjacent tracheary elements in flowering plants. Variation in the bordered pit structure is suggested to be adaptive in optimally balancing the conflict between hydraulic efficiency (conductivity) and safety from air entry at the pit membrane (air seeding). The possible function of vestured pits, which are bordered pits with protuberances from the secondary cell wall of the pit chamber, could be increased hydraulic resistance or minimized vulnerability to air seeding. These functional hypotheses have to be harmonized with the notion that the vestured or nonvestured nature of pits contains strong phylogenetic signals (i.e., often characterize large species-rich clades with broad ecological...
Tipo: Article / Letter to the editor
Palavras-chave: Xylem structure; Vestured pits; Scalariform perforation plates; Simple perforation plates; Hydraulic system; Drought stress; 42.42.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/423503

Vessel grouping patterns in subfamilies Apocynoideae and Periplocoideae confirm phylogenetic value of wood structure within Apocynaceae
Provedor de dados: 16
Autores: Lens, F.; Endress, M.E.; Baas, P.; Jansen, S.; Smets, E.; , D.
This study contributes to our understanding of the phylogenetic signifi cance and major evolutionary trends in the wood of the dogbane family (Apocynaceae), one of the largest and economically most important angiosperm families. Based on LM and SEM observations of 56 Apocynoideae species — representing all currently recognized tribes — and eight Periplocoideae, we found striking differences in vessel grouping patterns (radial multiples vs. large clusters) between the mainly nonclimbing apocynoid tribes (Wrightieae, Malouetieae, Nerieae) and the climbing lineages (remaining Apocynoideae and Periplocoideae). The presence of large vessel clusters in combination with fibers in the ground tissue characterizing the climbing Apocynoideae and Periplocoideae...
Tipo: Article / Letter to the editor
Palavras-chave: Apocynaceae; Apocynoideae; APSA clade; Climbing vs. nonclimbing anatomy; Periplocoideae; Systematic wood anatomy; Tribal classification; 42.58.
Ano: 2009
URL: http://www.repository.naturalis.nl/record/424670

Palynological Characters and Their Phylogenetic Signal in Rubiaceae
Provedor de dados: 16
Autores: 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

Relationships within balsaminoid Ericales: a wood anatomical approach
Provedor de dados: 16
Autores: Lens, F.; Dressler, S.; Jansen, S.; Van Evelghem, L.; Smets, E.
Wood samples of 49 specimens representing 31 species and 11 genera of woody balsaminoids, i.e., Balsaminaceae, Marcgraviaceae, Pellicieraceae, and Tetrameristaceae, were investigated using light microscopy and scanning electron microscopy. The wood structure of Marcgraviaceae, Pellicieraceae, and Tetrameristaceae is characterized by radial vessel multiples with simple perforation plates, alternate vessel pitting, apotracheal and paratracheal parenchyma, septate libriform fibers, and the presence of raphides in ray cells. Tetrameristaceae and Pellicieraceae are found to be closely related based on the occurrence of unilaterally compound vessel-ray pitting and multiseriate rays with long uniseriate ends. The narrow rays in Pelliciera are characteristic of...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminaceae; Balsaminoid clade; Ericales; Marcgraviaceae; Paedomorphism; Pellicieraceae; Tetrameristaceae; Wood anatomy; 42.40.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407273

Do quantitative vessel and pit characters account for ion-mediated changes in the hydraulic conductance of angiosperm xylem?
Provedor de dados: 16
Autores: Jansen, S.; Gortan, E.; Lens, F.; Assunta Lo Gullo, M.; Salleo, S.; Scholtz, A.; Stein, A.; Trifilò, P.; Nardini, A.
• The hydraulic conductance of angiosperm xylem has been suggested to vary with changes in sap solute concentrations because of intervessel pit properties.  • The magnitude of the ‘ionic effect’ was linked with vessel and pit dimensions in 20 angiosperm species covering 13 families including six Lauraceae species.  • A positive correlation was found between ionic effect and vessel grouping parameters, especially the portion of vessel walls in contact with neighbouring vessels. Species with intervessel contact fraction (FC) values &lt; 0.1 showed an ionic effect between 2% and 17%, while species with FC values &gt; 0.1 exhibited a response between 10% and 32%. The ionic effect increased linearly with the mean fraction of the total vessel wall area occupied...
Tipo: Article / Letter to the editor
Palavras-chave: Angiosperms; Hydraulic conductivity; Intervessel pit membrane; Ionic effect; Vessel grouping; Wood anatomy; 42.41.
Ano: 2011
URL: http://www.repository.naturalis.nl/record/423644

Woodiness within the Spermacoceae–Knoxieae alliance (Rubiaceae): retention of the basal woody condition in Rubiaceae or recent innovation?
Provedor de dados: 16
Autores: Lens, F.; Groeninkx, I.; Smets, E.; Dessein, S.
† Background and Aims The tribe Spermacoceae is essentially a herbaceous Rubiaceae lineage, except for some species that can be described as ‘woody’ herbs, small shrubs to treelets, or lianas. Its sister tribe Knoxieae contains a large number of herbaceous taxa, but the number of woody taxa is higher compared to Spermacoceae. The occurrence of herbaceous and woody species within the same group raises the question whether the woody taxa are derived from herbaceous taxa (i.e. secondary woodiness), or whether woodiness represents the ancestral state (i.e. primary woodiness). Microscopic observations of wood anatomy are combined with an independent molecular phylogeny to answer this question.  † Methods Observations of wood anatomy of 21 woody Spermacoceae and...
Tipo: Article / Letter to the editor
Palavras-chave: Knoxieae; LM; Primary woodiness; Rubiaceae; Rubioideae; Secondary woodiness; Spermacoceae; Wood anatomy; 42.56.
Ano: 2009
URL: http://www.repository.naturalis.nl/record/428974

The Micromorphology of Pit Membranes in Tracheary Elements of Ericales: New Records of Tori or Pseudo-tori?
Provedor de dados: 16
Autores: Rabaey, D.; Lens, F.; Smets, E.; Janssen, S.
Background and Aims Intervascular pit membranes were examined within Ericales to determine the distribution and structure of torus-like thickenings.   Methods Forty-nine species representing 12 families of the order Ericales were investigated using light, scanning and transmission electron microscopy. They were compared with four species of Oleaceae to determine the true nature of the thickenings.   Key Results Pit membranes with torus-like thickenings were observed in seven species of Ericaceae and were found to be amorphous, plasmodesmata-associated structures with an irregular distribution. These pseudo-tori show major differences compared with true tori with respect to their distribution and ultrastructure. Genuine tori, which are strongly correlated...
Tipo: Article / Letter to the editor
Palavras-chave: Ericaceae; Ericales; Oleaceae; Pit membrane; Plasmodesmata; Pseudo-torus; Torus; Tracheary elements.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407321

Vestured pits: a diagnostic character in the secondary xylem of Myrtales
Provedor de dados: 16
Autores: Jansen, S.; Pletsers, A.; Rabaey, D.; Lens, F.
Vestures are small projections from the secondary cell wall associated with tracheary elements of the secondary xylem. They are usually associated with bordered pits and characterize various angiosperm families, including important timber species such as Dipterocarpaceae and Eucalyptus trees. The micromorphology and distribution of vestures were studied in 22 species representing all families within the order Myrtales based on light and scanning electron microscopy. Vestures are consistently present near the outer pit aperture of bordered vessel pits, suggesting the synapomorphic character of this feature for the entire order. It is unclear in which geological period this feature originated in the evolution of the pre-Myrtalean lineages. In some species...
Tipo: Article / Letter to the editor
Palavras-chave: Vestures; Wood anatomy; Bordered pits; Myrtales; Scanning electron microscopy; Light microscopy; Tracheary elements; 42.48; 42.56.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/498037

Comparative wood anatomy of the blueberry tribe (Vaccinieae, Ericaceae s.l.)
Provedor de dados: 16
Autores: Lens, F.; Kron, K.A.; Luteyn, J.L.; Smets, E.; Jansen, S.
Wood samples of 111 Vaccinieae specimens (Vaccinioideae, Ericaceae s.l.) representing 98 species and 26 genera are investigated with light microscopy and scanning electron microscopy. The wood structure of Vaccinieae delivers taxonomically important characters that can be used to define some subclades within the tribe. The wood of the large polyphyletic genus Vaccinium strongly resembles non-vaccinioid members of the family, which are characterized by bordered vessel-ray pits and relatively narrow (2- to 4-seriate) and low multiseriate rays (often less than 1000 mm) with exclusively or mainly procumbent body ray cells. The East Malesian clade, Meso-American/Caribbean clade, and the Andean clade show a combination of wood anatomical features that is lacking...
Tipo: Article / Letter to the editor
Palavras-chave: Blueberries; Comparative wood anatomy; Ericaceae; Neotropics; Secretory ducts; Systematics; Vaccinieae; 42.56.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/423810

Ecological trends in the wood anatomy of Vaccinioideae (Ericaceae s.l.)
Provedor de dados: 16
Autores: Lens, F.; Luteyn, J.L.; Smets, E.; Jansen, S.
The ecological wood anatomy of 128 vaccinioid wood samples (including 115 species, 35 genera), collected between 39°S and 60°N latitude and 10 m to 3400 m altitude is studied. Several wood anatomical features within the subfamily, viz. tangential vessel diameter, average length of tracheary elements, height of multiseriate rays, and presence of prismatic crystals are negatively correlated with increasing latitude, while vessel density and helical thickenings show a positive correlation with increasing latitude. Similar latitudinal trends are found within the genus Vaccinium (31 species studied). The correlation between various wood anatomical features and latitude is surprisingly high despite the fact that most tropical species grow in montane regions,...
Tipo: Article / Letter to the editor
Palavras-chave: Altitude; Ecological and functional wood anatomy; Ericaceae; Latitude; Vaccinioideae; Vaccinium; 42.58.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/424624

The phylogenetic significance of vestured pits in Boraginaceae
Provedor de dados: 16
Autores: Rabaey, D.; Lens, F.; Smets, E.; Jansen, S.
The bordered pit structure in tracheary elements of 105 Boraginaceae species is studied using scanning electron microscopy to examine the systematic distribution of vestured pits. Forty-three species out of 16 genera show a uniform presence of this feature throughout their secondary xylem. Most vestures are small, unbranched and associated with the outer pit aperture of bordered intervessel pits. The feature is likely to have originated independently in the distantly related subfamilies Boraginoideae (tribe Lithospermeae) and Ehretioideae. The distribution of vestures in Ehretia agrees with recent molecular phylogenies: (1) species with vestured pits characterise the Ehretia I group (incl. Rotula), and (2) species with non-vestured pits belong to the...
Tipo: Article / Letter to the editor
Palavras-chave: Boraginaceae; Boraginoideae; Bordered pit; Ehretioideae; Scanning electron microscopy; Vestures; 42.56.
Ano: 2010
URL: http://www.repository.naturalis.nl/record/430079

TRY – a global database of plant traits
Provedor de dados: 16
Autores: Kattge, J.; Lens, F.
Plant traits – the morphological, anatomical, physiological, biochemical and phenological characteristics of plants and their organs – determine how primary producers respond to environmental factors, affect other trophic levels, influence ecosystem processes and services and provide a link from species richness to ecosystem functional diversity. Trait data thus represent the raw material for a wide range of research from evolutionary biology, community and functional ecology to biogeography. Here we present the global database initiative named TRY, which has united a wide range of the plant trait research community worldwide and gained an unprecedented buy-in of trait data: so far 93 trait databases have been contributed. The data repository currently...
Tipo: Article / Letter to the editor
Palavras-chave: Comparative ecology; Database; Environmental gradient; Functional diversity; Global analysis; Global change; Interspecific variation; Intraspecific variation; Plant attribute; Plant functional type; Plant trait; Vegetation model; 42.44.
Ano: 2011
URL: http://www.repository.naturalis.nl/record/423730

Embolism resistance as a key mechanism to understand adaptive plant strategies
Provedor de dados: 16
Autores: Lens, F.; Tixier, A.; Cochard, H.; Sperry, J.S.; Jansen, S.; Herbette, S.
One adaptation of plants to cope with drought or frost stress is to develop wood that is able to withstand the formation and distribution of air bubbles (emboli) in its water conducting xylem cells under negative pressure. The ultrastructure of interconduit pits strongly affects drought-induced embolism resistance, but also mechanical properties of the xylem are involved. The first experimental evidence for a lower embolism resistance in stems of herbaceous plants compared to stems of their secondarily woody descendants further supports this mechanical-functional trade-off. An integrative approach combining (ultra)structural observations of the xylem, safetyefficiency aspects of the hydraulic pipeline, and xylem–phloem interactions will shed more light on...
Tipo: Article / Letter to the editor
Palavras-chave: Embolism resistance; Adaptive plant strategies; Drought stress; Air bubbles (emboli); Xylem; 42.42.
Ano: 2013
URL: http://www.repository.naturalis.nl/record/453852

Contributions to the Wood Anatomy of the Rubioideae (Rubiaceae)
Provedor de dados: 16
Autores: Jansen, S.; Lens, F.; Ntore, S.; Piesschaert, F.; Robbrechf, E.; Smets, E.
The secondary xylem of Craterispermeae, Coussareeae, Morindeae s.str., Prismatomerideae, Pauridiantheae, Urophylleae, and Triainolepideae (Rubiaceae, Rubioideae) is described and illustrated in detail. Genera that were previously placed in the Morindeae or Psychotrieae such as Damnacanthus, Lasianthus, Saldinia, and Trichosfachys are also included. Wood anatomical characters are compared with recent phylogenetic insights into the study group on the basis of molecular data. The observations demonstrate that the delimitation and separation of several taxa from the former Coussareeae/Morindeae/Prismatomerideae/Psychotrieae aggregate is supported by wood anatomical data. The Coussareeae can be distinguished from the other Rubioideae by their scanty parenchyma,...
Tipo: Article / Letter to the editor
Palavras-chave: Rubiaceae; Rubioideae; Systematic wood anatomy; 42.58.
Ano: 2001
URL: http://www.repository.naturalis.nl/record/421859

Pit membranes in tracheary elements of Rosaceae and related families: New records of tori and pseudotori
Provedor de dados: 16
Autores: Jansen, S.; Sano, Y.; Choat, B.; Rabaey, D.; Lens, F.; Dute, R.R.
The micromorphology of pits in tracheary elements was examined in 35 species representing 29 genera of Rosaceae and related families to evaluate the assumption that angiosperm pits are largely invariant. In most Rosaceae, pit membranes between fibers and tracheids frequently appear to have amorphous thickenings with an irregular distribution. Although these structures are toruslike under the light microscope, observations by electron microscopy illustrate that they represent ‘‘pseudotori’’ or plasmodesmata-associated thickenings. These thickenings frequently extend from the periphery of the pit membrane and form a cap-like, hollow structure. Pseudotori are occasionally found in few Elaeagnaceae and Rhamnaceae and appear to be related to species with...
Tipo: Article / Letter to the editor
Palavras-chave: Fiber; Pit; Pit membrane; Pseudotorus; Rosaceae; Rosales; Torus; Tracheid; 42.58.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/423505

A comparative ultrastructural study of pit membranes with plasmodesmata associated thickenings in four angiosperm species
Provedor de dados: 16
Autores: 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

Wood anatomy of  Rauvolfioideae (Apocynaceae): a search for meaningful non-DNA characters at the tribal level
Provedor de dados: 16
Autores: Lens, F.; Endress, M.E.; Baas, P.; Jansen, S.; Smets, E.
Wood anatomical studies in the economically important Apocynaceae or dogbane family are fragmentary. This study represents a first attempt to unravel the phylogenetic signifi cance and major evolutionary trends in the wood of the family, using existing and new microscopic wood observations within the large subfamily Rauvolfi oideae. On the basis of LM and SEM observations of 91 species representing all 10 currently recognized tribes, we found that most of the tribes are characterized by a unique combination of wood characters, such as vessel grouping, vessel element length, fi ber type, frequency of uniseriate rays, and fused multiseriate rays. Climbing rauvolfi oid taxa can generally be distinguished from erect species by their wider vessels, tendency to...
Tipo: Article / Letter to the editor
Palavras-chave: Apocynaceae; APSA clade; Climbing vs. nonclimbing habit; Rauvolfi oideae; Systematic wood anatomy; Tribal classification; 42.58.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/424647

Stem anatomy supports Arabidopsis thaliana as a model for insular woodiness
Provedor de dados: 16
Autores: Lens, F.; Smets, E.; Melzer, S.
The soc1 ful double mutant of A. thaliana produced substantial secondary growth throughout all aboveground stems, whereas in the Col accession only a few cell layers of wood were produced at the base of old stems. This increased wood formation may be linked to inactivation of the flowering time genes SOC1 and FUL (Melzer et al., 2008). These two genes could play a crucial regulatory role in triggering genetic mechanisms that lead to insular woodiness outside A. thaliana, and this ‘simple’ two-gene loss could explain why many nonrelated herbaceous families have independently evolved into woody insular lineages throughout the world. However, SOC1 and FUL might not be the only suppressors of cambium formation; other upstream, downstream or parallel-acting...
Tipo: Article / Letter to the editor
Palavras-chave: Stem anatomy; Arabidopsis thaliana; Insular woodiness; Brassicaceae; Wood formation; 42.56.
Ano: 2012
URL: http://www.repository.naturalis.nl/record/429528

Global convergence in the vulnerability of forests to drought
Provedor de dados: 16
Autores: Choat, B.; Jansen, S.; Brodribb, T.J.; Cochard, H.; Delzon, S.; Bhaskar, R.; Bucci, S.J.; Feild, T.S.; Gleason, S.M.; Hacke, U.G.; Jacobsen, A.L.; Lens, F.; Maherali, H.; Martínez-Vilalta, J.; Mayr, S.; Mencuccini, M.; Mitchell, P.J.; Nardini, A.; Pittermann, J.; Pratt, R.B.; Sperry, J.S.; Westoby, M.; Wright, I.J.; Zanne, A.E.
Shifts in rainfall patterns and increasing temperatures associated with climate change are likely to cause widespread forest decline in regions where droughts are predicted to increase in duration and severity. One primary cause of productivity loss and plant mortality during drought is hydraulic failure. Drought stress creates trapped gas emboli in the water transport system, which reduces the ability of plants to supply water to leaves for photosynthetic gas exchange and can ultimately result in desiccation and mortality. At present we lack a clear picture of how thresholds to hydraulic failure vary across a broad range of species and environments, despite many individual experiments. Here we draw together published and unpublished data on the...
Tipo: Article / Letter to the editor
Palavras-chave: Global convergence vulnerability forests drought climate change drought-induced forest decline 42.44; 43.47.
Ano: 2012
URL: http://www.repository.naturalis.nl/record/453830

Micromorphology and systematic distribution of pit membrane thickenings in Oleaceae: Tori and pseudo-tori
Provedor de dados: 16
Autores: 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

The wood anatomy of the polyphyletic Icacinaceae s.l., and their relationships within asterids
Provedor de dados: 16
Autores: 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

Evolution of fruit and seed characters in the Diervilla and Lonicera clades (Caprifoliaceae, Dipsacales)
Provedor de dados: 16
Autores: Jacobs, B.; Lens, F.; Smets, E.
Background and Aims: The Diervilla and Lonicera clades are members of the family Caprifoliaceae (Dipsacales sensu Donoghue et al., 2001, Harvard Papers in Botany 6: 459–479). So far, the intergeneric relationships of the Lonicera clade and the systematic position of Heptacodium remain equivocal. By studying fruit and seed morphology and anatomy, an attempt is made to clarify these issues. In addition, this study deals with the evolution of fruit and seed characters of the Diervilla and Lonicera clades with reference to allied taxa.  Methods: Light and scanning electron microscopy were used for the morphological and anatomical investigations. Phylogenetic analyses were carried out by applying the parsimony and Bayesian inference optimality criteria....
Tipo: Article / Letter to the editor
Palavras-chave: Diervilla; Weigela; Symphoricarpos; Lonicera; Triosteum; Leycesteria; Heptacodium; Caprifoliaceae; Dipsacales; Fruit; Seed; Evolution; 42.56.
Ano: 2009
URL: http://www.repository.naturalis.nl/record/421854

Pollination and protection against herbivory of Nepalese Coelogyninae (Orchidaceae)
Provedor de dados: 16
Autores: Subedi, A.; Chaudhary, R.P.; Achterberg, C. van; Heijerman, T.; Lens, F.; Dooren, T.J.M. van; Gravendeel, B.
• Premise of the Study: Although many species in the orchid genus Coelogyne are horticulturally popular, hardly anything is known about their pollination. Pollinators of three species were observed in the fi eld in Nepal. This information is urgently needed because many orchid species in Nepal are endangered. Whether the exudates produced by extrafl oral nectaries played a role in protection against herbivory was also investigated.  • Methods: Pollinators of C. fl accida , C. nitida , and Otochilus albus were filmed, captured, and identifi ed. Ant surveys and exclusion experiments were carried out. To investigate whether pollinators are needed for fruit set, plants were wrapped in mesh wire bags. Infl orescence stems were examined with microscopy. Fehling...
Tipo: Article / Letter to the editor
Palavras-chave: Ants; Apis cerana; Bombus kashmirensis; Coelogye; Herbivory; Nectary-modified stomata; Nepal; Otochilus; Pholidota; Pollination.
Ano: 2011
URL: http://www.repository.naturalis.nl/record/430082

Phylogenetic and ecological signals in the wood of Spathelioideae (Rutaceae)
Provedor de dados: 16
Autores: Appelhans, M.S.; Heuven, B.J. van; Lens, F.; Baas, P.
Subfamily Spathelioideae of Rutaceae constitutes a well-supported early branching clade of eight small woody genera that were formerly assigned to five different Sapindalean/Rutalean families. This study brings together detailed wood anatomical information on all eight genera (for four the wood anatomy is described for the first time in detail). Wood anatomy strongly supports the inclusion of all Spathelioid genera in Rutaceae and underpins the molecular phylogeny with a set of interesting apomorphies at different nodes of the cladogram. The wood anatomy of Cneorum tricoccon with its semi-ring porosity, dendritic vessel pattern, vascular tracheids and helical vessel wall thickenings stands out in Spathelioideae. This wood anatomical syndrome is...
Tipo: Article / Letter to the editor
Palavras-chave: Cneorum; Dictyoloma; Harrisonia; Sohnreyia; Spathelia; Vessel grouping; Hydraulic safety; Prismatic crystals; Xylem rays; 42.48.
Ano: 2012
URL: http://www.repository.naturalis.nl/record/497323

The role of wood anatomy in phylogeny reconstruction of Ericales
Provedor de dados: 16
Autores: Lens, F.; Schönenberger, J.; Baas, P.; Jansen, S.; Smets, E.
The systematic significance of wood anatomical characters within Ericales is evaluated using separate and combined parsimony analyses including 23 wood characters and 3945 informative molecular characters. Analyses of wood features alone result in poorly resolved and conflicting topologies. However, when pedomorphic character states are coded as inapplicable, the combined bootstrap topology results in an increase of resolution and support at most deeper nodes compared with the molecular analyses. This suggests that phylogenetic information from the limited number of morphological characters is not completely swamped by an overwhelming amount of molecular data. Based on the morphology of vessels and fibers, and the distribution of axial parenchyma, two...
Tipo: Article / Letter to the editor
Palavras-chave: Anatomy; Phylogeny; Ericales; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/422235

Wood anatomy of the Vanguerieae (Ixoroideae - Rubiaceae), with special emphasis on some geofrutices
Provedor de dados: 16
Autores: Lens, F.; Jansen, S.; Robbrecht, E.; Smets, E.
The Vanguerieae is a tribe consisting of about 500 species ordered in 27 genera. Although this tribe is mainly represented in Africa and Madagascar, Vanguerieae also occur in tropical Asia, Australia, and the isles of the Pacific Ocean. This study gives a detailed wood anatomical description of 34 species of 15 genera based on LM and SEM observations. The secondary xylem is homogeneous throughout the tribe and fits well into the Ixoroideae s.l. on the basis of fibre-tracheids and diffuse to diffuse-in-aggregates axial parenchyma. The Vanguerieae include numerous geofrutices that are characterised by massive woody branched or unbranched underground parts and slightly ramified unbranched aboveground twigs. The underground structures of geofrutices are not...
Tipo: Article / Letter to the editor
Palavras-chave: Vanguereae; Rubiaceae; Systematic wood anatomy; Geofrutex; 42.58.
Ano: 2000
URL: http://www.repository.naturalis.nl/record/423793

Pollen morphological variation in Vanguerieae (Ixoroideae - Rubiaceae)
Provedor de dados: 16
Autores: 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

Intervascular pit membranes with a torus in the wood of Ulmus (Ulmaceae) and related genera
Provedor de dados: 16
Autores: Jansen, S.; Choat, B.; Vinckier, S.; Lens, F.; Schols, P.; Smets, E.
• The distribution of intervascular pit membranes with a torus was investigated in juvenile wood samples of 19 species of Ulmus and seven related genera.  • A staining solution of safranin and alcian blue (35 : 65) was recommended to distinguish torus-bearing pit membranes using light microscopy.  • Intervascular pit membranes connecting relatively wide vessel elements resembled those of most angiosperms, as they were of uniform thickness. By contrast, bordered pit pairs with round to oval pit apertures and indistinct pit canals that connected narrow (incomplete) vessel elements or vascular tracheids with distinct helical thickenings were frequently characterized by a torus in ring-porous wood samples of Ulmus and Zelkova. Tori were lacking in...
Tipo: Article / Letter to the editor
Palavras-chave: Ulmus (elm); Ulmaceae; Pit membrane; Torus; Pit structure; Wood anatomy; Tracheary elements; 42.58.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/423388

Insular woodiness on the Canary Islands: a remarkable case of convergent evolution
Provedor de dados: 16
Autores: Lens, F.; Davin, N.; Smets, E.; Arco, M. del.
Premise of research.   One of the most conspicuous aspects of island floras is the relatively high proportion of woody species. Often, but not always, these woody species have developed wood on the islands and have evolved from herbaceous continental ancestors, a phenomenon known as insular woodiness. Shifts from herbaceousness toward increased woodiness also occur on continents (the broader term “secondary woodiness” is more appropriate here and includes insular woodiness), but comprehensive worldwide knowledge about secondary woodiness within angiosperms remains lacking. We update hypotheses regarding the herbaceous ancestry of woody Canarian lineages in a molecular phylogenetic context and investigate the possible link of secondary woodiness and...
Tipo: Article / Letter to the editor
Palavras-chave: Canary Islands convergent evolution insular woodiness molecular phylogeny protracted juvenilism seconday woodinessq wood anatomy 42.21; 42.44.
Ano: 2013
URL: http://www.repository.naturalis.nl/record/453855

Testing hypotheses that link wood anatomy to cavitation resistance and hydraulic conductivity in the genus Acer
Provedor de dados: 16
Autores: Lens, F.; Sperry, J.S.; Christmas, M.A.; Rabaey, D.; Jansen, S.
• Vulnerability to cavitation and conductive efficiency depend on xylem anatomy. We tested a large range of structure–function hypotheses, some for the first time, within a single genus to minimize phylogenetic ‘noise’ and maximize detection of functionally relevant variation.  • This integrative study combined in-depth anatomical observations using light, scanning and transmission electron microscopy of seven Acer taxa, and compared these observations with empirical measures of xylem hydraulics.  • Our results reveal a 2 MPa range in species’ mean cavitation pressure (MCP). MCP was strongly correlated with intervessel pit structure (membrane thickness and porosity, chamber depth), weakly correlated with pit number per vessel, and not related to pit area...
Tipo: Article / Letter to the editor
Palavras-chave: Acer; Cavitation resistance; Hydraulic conductivity; Pit structure; Rare pit hypothesis; Vessel distribution; Vessel wall thickenings; Wood density; 42.56.
Ano: 2011
URL: http://www.repository.naturalis.nl/record/429474

Palynological Variation in Balsaminoid Ericales. I. Marcgraviaceae
Provedor de dados: 16
Autores: Lens, F.; Dressler, S.; Vinckier, S.; Janssens, S.; Dessein, S.; Van Evelghem, L.; Smets, E.
Background and Aims Marcgraviaceae are a rather small family of seven genera and approx. 130 neotropical species. This study aims to present a detailed palynological survey of the family in order to comment on the intrafamily relationships and possible correlations with pollinators. Methods In total, 119 specimens representing 67 species and all genera are observed using light microscopy and scanning electron microscopy. Furthermore, eight species from five genera are studied with transmission electron microscopy.  Key Results Our results show that pollen grains of Marcgraviaceae are small (20–35 mm), have three equatorial apertures, granules on the colpus membrane, oblate spheroidal to prolate spheroidal shapes, mainly psilate to perforate ornamentations,...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminoids; Ericales; Marcgraviaceae; Neotropics; Orbicules; Palynology; SEM; TEM.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407283

Palynological Variation in Balsaminoid Ericales. II. Balsaminaceae, Tetrameristaceae, Pellicieraceae and General Conclusions
Provedor de dados: 16
Autores: Janssens, S.; Lens, F.; Dressler, S.; Geuten, K.; Smets, E.; Vinckier, S.
Background and Aims The objective of this study is to examine the palynological diversity of Balsaminaceae (two genera/61000 species), Tetrameristaceae (two genera/two species) and Pellicieraceae (one genus/one species). The diversity found will be used to infer the systematic value of pollen features within the balsaminoid clade.  Methods Pollen morphology and ultrastructure of 29 species, representing all families of the balsaminoid clade except Marcgraviaceae, are investigated by means of light microscopy, scanning electron microscopy and transmission electron microscopy.  Key Results Balsaminaceae pollen is small to medium sized with three to four apertures, which can be either colpate or porate, and a sexine sculpturing varying from coarsely...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminaceae; Ericales; Orbicules; Pellicieraceae; Pollen; SEM; TEM; Tetrameristaceae.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407278

Comparative Wood Anatomy of the Primuloid Clade (Ericales s.l.)
Provedor de dados: 16
Autores: Lens, F.; Jansen, S.; Caris, P.; Serlet, L.; Smets, E.
The wood structure of 78 species from 27 genera representing the woody primuloids (Maesaceae, Myrsinaceae, and Theophrastaceae) was investigated using light microscopy (LM) and scanning electron microscopy (SEM). Results indicated that the ray structure, the nature of mineral inclusions, and the occurrence of breakdown areas in rays can be used to separate the three primuloid families from each other. Within Ericales, the presence of exclusively multiseriate rays is synapomorphic for Myrsinaceae and Theophrastaceae, and the occurrence of breakdown areas in rays is synapomorphic for Myrsinaceae. Within Myrsinaceae, the wood structure of the mangrove genus Aegiceras differs because it has short vessel elements that are storied, non-septate fibers, a...
Tipo: Article / Letter to the editor
Palavras-chave: Primuloids; Ericales s.l.; Maesaceae; Myrsinaceae; Theophrastaceae; Wood anatomy; Comparison; Light microscopy; Scanning electron microscopy.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407307

A comparison of paraffin and resin-based techniques used in bark anatomy
Provedor de dados: 16
Autores: Hamann, T.; Smets, E.; Lens, F.
Bark anatomy is an unappreciated discipline in plant systematics, despite its great potential to reveal systematically informative features. In this paper, main reasons for the lack of detailed bark anatomical data in many plant families are identified, including problems with sectioning, terminological issues, and difficulties in observation of dilated stems. We deal with these problems by focusing on two aspects: (1) compare, discuss and improve existing sectioning and maceration techniques using two species with soft and hard bark tissues; and (2) discuss the best way to collect stem bark samples. We hope that this paper will stimulate inclusion of bark anatomical data in future systematic studies.
Tipo: Article / Letter to the editor
Palavras-chave: Bark anatomy; Light microscopy; Macerations; Plant systematics; Phloem; Sectioning; 42.54.
Ano: 2011
URL: http://www.repository.naturalis.nl/record/421834

The multiple fuzzy origins of woodiness within Balsaminaceae using an integrated approach. Where do we draw the line?
Provedor de dados: 16
Autores: Lens, F.; Eeckhout, S.; Zwartjes, R.; Smets, E.; Janssens, S.B.
• Background and Aims: The family Balsaminaceae is essentially herbaceous, except for some woodier species that can be described as ‘woody’ herbs or small shrubs. The family is nested within the so-called balsaminoid clade of Ericales, including the exclusively woody families Tetrameristaceae and Marcgraviaceae, which is sister to the remaining families of the predominantly woody order. A molecular phylogeny of Balsaminaceaeis compared with wood anatomical observations to find out whether the woodier species are derived from herbaceous taxa (i.e. secondary woodiness), or whether woodiness in the family represents the ancestral state for the order (i.e. primary woodiness).  • Methods: Wood anatomical observations of 68 Impatiens species and Hydrocera...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminaceae; Herbaceousness; Hydrocera; Impatiens; Insular woodiness; Light microscopy; Secondary woodiness; Wood anatomy; 42.56.
Ano: 2012
URL: http://www.repository.naturalis.nl/record/429514

An extension of the Plant Ontology project supporting wood anatomy and development research
Provedor de dados: 16
Autores: Lens, F.; Cooper, L.; Gandolfo, M.A.; Groover, A.; Jaiswal, P.; Lachenbruch, B.; Spicer, R.; Staton, M.E.; Stevenson, D.W.; Walls, R.L.; Wegrzyn, J.
The Wood Ontology project will provide a structured vocabulary and database resource that will be valuable for all scientists, including the IAWA community. To maximizethe utility of the resource and analyses it empowers, it is important for researchers to adopt the use of the ontology terms in the collection and dissemination of their data. The PO website (www.plantontology.org) is the main portal for the Plant Ontology, and presents the current version.
Tipo: Article / Letter to the editor
Palavras-chave: Plant Ontology; Wood anatomy and development; Plant morphology; Structured vocabulary; Database resource; 42.40.
Ano: 2012
URL: http://www.repository.naturalis.nl/record/429515

The distribution and phylogeny of aluminium accumulating plants in the Ericales
Provedor de dados: 16
Autores: Jansen, S.; Watanabe, T.; Caris, P.; Geuten, K.; Lens, F.; Pyck, N.; Smets, E.
The distribution of aluminium (Al) accumulation in the Ericales is surveyed, based on semi-quantitative tests of 114 species and literature data. Al accumulation mainly characterises the families Diapensiaceae, Pentaphylacaceae, Symplocaceae, Ternstroemiaceae, and Theaceae. Al accumulation is consistently present or absent in most families examined, but the character appears to be more variable in a few taxa (e.g., Lecythidaceae, Myrsinaceae). Although the interfamilial relationships within the Ericales require further research, the ability to accumulate high levels of Al appears to show considerable taxonomic significance. While the majority of Al accumulating Ericales includes woody, tropical plants, the feature is remarkably present in several...
Tipo: Article / Letter to the editor
Palavras-chave: Aluminium accumulation; Ericales; Phyogeny; Diapensiaceae; Pentaphylacaceae; Symplocaceae; Ternstroemiaceae; Theaceae; 42.56.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/431739

Comparative wood anatomy of epacrids (Styphelioideae, Ericaceae s.l.)
Provedor de dados: 16
Autores: Lens, F.; Gasson, P.; Smets, E.; Jansen, S.
The wood anatomy of 16 of the 37 genera within the epacrids (Styphelioideae, Ericaceae s.l.) is investigated by light and scanning electron microscopy. Several features in the secondary xylem occur consistently at the tribal level: arrangement of vessel‐ray pits, distribution of axial parenchyma, ray width, and the presence and location of crystals. The primitive nature of Prionoteae and Archerieae is supported by the presence of scalariform perforation plates with many bars and scalariform to opposite vessel pitting. The wood structure of Oligarrheneae is similar to that of Styphelieae, but the very narrow vessel elements, exclusively uniseriate rays and the lack of prismatic crystals in Oligarrheneae distinguish these two tribes. The secondary xylem of...
Tipo: Article / Letter to the editor
Palavras-chave: Ecological wood anatomy; Epacrids; Ericaceae s.l.; Styphelioideae; Systematic wood anatomy; 42.56.
Ano: 2003
URL: http://www.repository.naturalis.nl/record/431740