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Wood Anatomy (wood + anatomy)
Selected AbstractsLithocarpuslongzhouicus comb. nov. (Fagaceae) from China: based on morphological and molecular dataNORDIC JOURNAL OF BOTANY, Issue 2 2009Li Chen The taxonomic position of Castanopsis longzhouica C. C. Huang & Y. T. Chang has been controversial. Various authors included it in Castanopsis (D. Don) Spach, or Lithocarpus Bl. based on morphology, palynology and wood anatomy. In order to investigate this issue, sequences of nuclear ITS and the chloroplast genes matK and trnL-F of C. longzhouica were analyzed together with 72 representatives of 7 genera within Fagaceae. As for species of Lithocarpus, there were a 1-bp insertion and two unique 3-bp deletions from ITS2 of C. longzhouica distinguishing it from Castanopsis. The phylogenetic analyses on the separate ITS data and the joint data (ITS+matK+ trnL-F) strongly supported a derived position of C. longzhouica within a clade consisting of members of Lithocarpus. The result is consistent with previous suggestions based on wood anatomy, suggesting that C. longzhouica should be transferred to Lithocarpus. In addition, the shallow cup-shaped, loose incoherent-scale and indehiscent cupule and the concave scar of C. longzhouica suggests a close relationship to species of Lithocarpus. Based on these data, the new combination Lithocarpus longzhouicus (C. C. Huang & Y. T. Chang) J. Q. Li & L. Chen is proposed. [source] Carbon isotope discrimination and wood anatomy variations in mixed stands of Quercus robur and Quercus petraeaPLANT CELL & ENVIRONMENT, Issue 8 2001S. Ponton Abstract The two most common oak species in western Europe, Quercus robur and Quercus petraea, display different ecological behaviours, particularly with respect to their responses to drought. The ecophysiological basis of this niche difference is not understood well. Here we test the hypothesis that these two species present distinct water use efficiencies (WUEs), using the carbon isotope discrimination approach. Leaves and 13 dated ring sequences were sampled in 10 pairs of adult trees growing side by side. Carbon isotope composition was measured on cellulose extracts. In addition, relationships between carbon isotope discrimination and wood anatomy were assessed at the tree level. Quercus robur displayed a 1·0, larger isotopic discrimination than Q. petraea, and therefore a lower intrinsic WUE (,13%). This interspecific difference of isotopic discrimination was quite stable with time and independent of tree radial growth and climate fluctuations. A strong positive correlation was observed between average tree values of earlywood vessel surface area and 13C isotopic discrimination. This correlation was even higher with 13C of the 1976 dry year (r = 0·86). These observations led to the hypothesis that hydraulic properties of xylem could exert a constraint on leaf gas exchange, resulting in a larger WUE for individuals with smaller vessel cross-section area. [source] Dicotyledonous wood anatomy and the APG system of angiosperm classificationBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1-2 2000PIETER BAAS FLS The recently proposed classification by the Angiosperm Phylogeny Group (APG) of angiosperms based on monophyletic groups as recognized mainly by molccular analysis is used here to discuss wood anatomical diversity patterns at the ordinal level. The APG orders are compared with the most recent ,classical' orders as listed in the second edition of 7 h e Plant Book for ,improved' or ,deteriorated' wood anatomical coherence. Although homoplasy in wood anatomical characters, largely due to ecoloqical adaptations, limits the value of wood anatomy at higher levels of classification, many families and orders tend to have characteristic combinations of microscopic wood features. Out of the 29 APG dicot orders, seven (Aquifoliales, Cucurbitales, Gentianales, Geraniales, Myrtales, Sapindales, Saxifragales) show an increase in wood anatomical homogeneity relative to their ,classical' predecessors; four APG dicot orders (Apiales, Ericales, Fabales, and Rosales) show a drcrrase, although within the orders several suprafamilial subclades are homogeneous. For the remaining 18 orders. wood anatomical diversity remains about the same as in previous classfications or the APG ordinal composition is almost identical to the ,classical' composition. The results support the value of both molecular markers and wood anatomical characters in phylogenetic classification. Because the ,classical' ordinal classifications have been partly inspired by wood anatomical information, one might have expected a ?greater wood anatomical coherence in them than in the largely molecularly delimited APG orders if wood anatomy did not provide significant phylogenetic sisgnals at higher taxonomic levels. The reverse appears to be the case. Among the wood anatomical characters included in the comparison, vestured intervessel pits, large and simple ray parenchyma pits, and sometimes also wide and tall rays appear to characterize orders. Some orders tend to be characterized by a combination of ,primitive' features in the Baileyan sense: scalariform perforations, fibres with distinctly bordered pits, apotracheal parenchyma, and heterocellular rays. This raises the question as to whethcr in thcsc cladcs this entire combination of characteristics should not he viewrd as synapomorphic rather than symplesiomorphic. [source] Pollen morphology and wood anatomy of the Crudia group (Leguminosae, Caesalpinioideae, Detarieae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1-2 2000HANNAH BANKS Pollen from all 12 and wood from 11 genera in the Crudia group have been examined using light, scanning electron and transmission electron microscopy. This group is currently of systematic interest because it is part of a tribe undergoing taxonomic revision. The pollen grains fall into four groups: (1) Oxystigma, Kingiodendmn, Gossweilerodendron, Bathiaea,.Neoapaloxylon, Stemonocoleus, Guibourlia and Prioria have pollen of a widespread and generalized cacsalpinioid type that are small to medium sized, spheroidal to prolate, tricolporate and with a perforate exine, with some variation in surface ornamentation, aperture margins and ultrastructure. (2) Crudia pollen is tricolporate, coarsely striate with a coarsely scabrate to vcrmiculate aperture membrane. (3) Augouardia is tricolporate and coarsely reticulate. (4) Hardwickia and Colophosperrnum are pantoporate and reticulate or microreticulate-rugulate. The wood of Prioria, Oxystigma, Kingiodendmn and Gossweilerodendron has diffusely arranged axial canals, and these are four genera that have recently been merged into Prioria. Bathiaea has tangentially arranged axial canals. The other genera lack normal axial canals. Crudia is distinct, with banded parenchyma and variably storied short rays, Augouardia has much less abundant axial parenchyma that is mainly scanty paratracheal and vasiccntric, Guibourtia has mainly aliform parenchyma and rays variable in height and width, and Colophosperrnum and Hardwickia have similar paratracheal parenchyma patterns, although the rays tend to be wider in the latter. Our conclusion is that the Crudia group is not monophyletic. [source] The role of wood anatomy in phylogeny reconstruction of EricalesCLADISTICS, Issue 3 2007Frederic Lens 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 major wood types can be distinguished within Ericales: (i) a "primitive" type, nearly identical to the wood structure in the more basal outgroup Cornales, which is likely to have persisted in one major clade, and (ii) a "derived" type that must have evolved in at least two separate evolutionary lines. The occurrence of the first type is strongly correlated with shrubs to small trees growing in cold temperate or tropical montane regions, while the second type is common in tall trees of tropical lowlands. This favors the inclusion of ecologically adaptive features in phylogeny reconstruction. © The Willi Hennig Society 2006. [source] | ||||||||||