Records |
Author |
Christensen-Dalsgaard, K.K.; Ennos, A.R.; Fournier, M. |
Title |
Changes in hydraulic conductivity, mechanical properties, and density reflecting the fall in strain along the lateral roots of two species of tropical trees |
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Journal Article |
Year |
2007 |
Publication |
Journal of Experimental Botany |
Abbreviated Journal |
J. Exp. Bot. |
Volume |
58 |
Issue |
15-16 |
Pages |
4095-4105 |
Keywords |
Buttress roots; Density; Hydraulic conductivity; Hydraulic-mechanical trade-offs; Modulus of elasticity; Tropical trees; Wood; Elastic moduli; Hydraulic conductivity; Wood; Buttress roots; Hydraulic-mechanical trade-offs; Tropical trees; Forestry; water; article; biomechanics; histology; legume; physiology; plant root; plant stem; tree; wood; Xylopia; Biomechanics; Fabaceae; Plant Roots; Plant Stems; Trees; Water; Wood; Xylopia; Conductivity; Elastic Strength; Forestry; Wood |
Abstract |
Roots have been described as having larger vessels and so greater hydraulic efficiency than the stem. Differences in the strength and stiffness of the tissue within the root system itself are thought to be an adaptation to the loading conditions experienced by the roots and to be related to differences in density. It is not known how potential mechanical adaptations may affect the hydraulic properties of the roots. The change in strength, stiffness, conductivity, density, sapwood area, and second moment of area distally along the lateral roots of two tropical tree species in which the strain is known to decrease rapidly was studied and the values were compared with those of the trunk. It was found that as the strain fell distally along the roots, so did the strength and stiffness of the tissue, whereas the conductivity increased exponentially. These changes appeared to be related to differences in density. In contrast to the distal-most roots, the tissue of the proximal roots had a lower conductivity and higher strength than that of the trunk. This suggests that mechanical requirements on the structure rather than the water potential gradient from roots to branches are responsible for the general pattern that roots have larger vessels than the stem. In spite of their increased transectional area, the buttressed proximal roots were subjected to higher levels of stress and had a lower total conductivity than the rest of the root system. © 2007 The Author(s). |
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AgroParisTech, LERFOB, Ecole Nationale du Genie Rural, des Eaux et Forêts, 14 Avenue Girardet-CS 4216, 54000 Nancy Cedex, France |
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00220957 (Issn) |
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Cited By (since 1996): 6; Export Date: 22 October 2011; Source: Scopus; Coden: Jeboa; doi: 10.1093/jxb/erm268; PubMed ID: 18039738; Language of Original Document: English; Correspondence Address: Christensen-Dalsgaard, K.K.; University of Manchester, Faculty of Life Sciences, Jackson's Mill, Manchester M60 1QD, United Kingdom; email: karen@cd-mail.dk; Chemicals/CAS: water, 7732-18-5; Water, 7732-18-5 |
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EcoFoG @ webmaster @ |
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353 |
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Dejean, A.; Moreau, C.S.; Uzac, P.; Le Breton, J.; Kenne, M. |
Title |
The predatory behavior of Pheidole megacephala |
Type |
Journal Article |
Year |
2007 |
Publication |
Comptes Rendus Biologies |
Abbreviated Journal |
C. R. Biol. |
Volume |
330 |
Issue |
9 |
Pages |
701-709 |
Keywords |
Invasive ants; Landmarks; Pheidole megacephala; Predatory behavior; Recruitment; pheromone; ant; behavioral ecology; foraging behavior; invasive species; nest predation; pheromone; predator-prey interaction; animal experiment; ant; article; competitor species; controlled study; foraging behavior; host range; Isoptera; nest predation; nonhuman; predation; predator prey interaction; prey selection; species invasion; worker (insect); Animals; Ants; Feeding Behavior; Female; Isoptera; Predatory Behavior; Social Behavior; Formicidae; Hexapoda; Isoptera; Pheidole megacephala |
Abstract |
We studied the foraging and predatory behaviors of the invasive African myrmicine ant, Pheidole megacephala (F.) in its native range. Workers can singly capture a wide range of insects, including relatively large prey items. For still larger prey, they recruit at short range those nestmates situated within reach of an alarm pheromone and together spread-eagle the insect. These behaviors are complimented by a long-range recruitment (of nestmates remaining in the nest) based on prey size. P. megacephala scouts also use long-range recruitment when they detect the landmarks of termites and competing ant species, thus permitting them to avoid confronting these termites and ants solitarily. |
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Département de biologie des organismes animaux, faculté des sciences, l'université de Douala, BP 24157, Douala, Cameroon |
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16310691 (Issn) |
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Cited By (since 1996): 8; Export Date: 22 October 2011; Source: Scopus; Coden: Crboc; doi: 10.1016/j.crvi.2007.06.005; PubMed ID: 17720587; Language of Original Document: English; Correspondence Address: Dejean, A.; CNRS-Guyane, UPS 2561, UMR-CNRS 5174, 16, avenue André-Aron, 97300 Cayenne, France; email: alain.dejean@wanadoo.fr |
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EcoFoG @ webmaster @ |
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354 |
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Gourlet-Fleury, S.; Rossi, V.; Rejou-Mechain, M.; Freycon, V.; Fayolle, A.; Saint-André, L.; Cornu, G.; Gérard, J.; Sarrailh, J.-M.; Flores, O.; Baya, F.; Billand, A.; Fauvet, N.; Gally, M.; Henry, M.; Hubert, D.; Pasquier, A.; Picard, N. |
Title |
Environmental filtering of dense-wooded species controls above-ground biomass stored in African moist forests |
Type |
Journal Article |
Year |
2011 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
Volume |
99 |
Issue |
4 |
Pages |
981-990 |
Keywords |
Basal area; Central African Republic; Determinants of plant community diversity and structure; Life-history strategy; Soil fertility; Species sorting; Vital rates; Water reserve; Wood density; aboveground biomass; basal area; climate change; data set; database; diameter; forest ecosystem; forest inventory; life history trait; nutrient availability; physical property; plant community; resource availability; soil fertility; soil nutrient; soil texture; soil type; stem; tropical forest; wood; Central African Republic |
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1.Regional above-ground biomass estimates for tropical moist forests remain highly inaccurate mostly because they are based on extrapolations from a few plots scattered across a limited range of soils and other environmental conditions. When such conditions impact biomass, the estimation is biased. The effect of soil types on biomass has especially yielded controversial results. 2.We investigated the relationship between above-ground biomass and soil type in undisturbed moist forests in the Central African Republic. We tested the effects of soil texture, as a surrogate for soil resources availability and physical constraints (soil depth and hydromorphy) on biomass. Forest inventory data were collected for trees ≥20cm stem diameter in 2754 0.5ha plots scattered over 4888km2. The plots contained 224 taxons, of which 209 were identified to species. Soil types were characterized from a 1:1000000 scale soil map. Species-specific values for wood density were extracted from the CIRAD's data base of wood technological properties. 3.We found that basal area and biomass differ in their responses to soil type, ranging from 17.8m2ha-1 (217.5tha-1) to 22.3m2ha-1 (273.3tha-1). While shallow and hydromorphic soils support forests with both low stem basal area and low biomass, forests on deep resource-poor soils are typically low in basal area but as high in biomass as forests on deep resource-rich soils. We demonstrated that the environmental filtering of slow growing dense-wooded species on resource-poor soils compensates for the low basal area, and we discuss whether this filtering effect is due to low fertility or to low water reserve. 4.Synthesis. We showed that soil physical conditions constrained the amount of biomass stored in tropical moist forests. Contrary to previous reports, our results suggest that biomass is similar on resource-poor and resource-rich soils. This finding highlights both the importance of taking into account soil characteristics and species wood density when trying to predict regional patterns of biomass. Our findings have implications for the evaluation of biomass stocks in tropical forests, in the context of the international negotiations on climate change. © 2011 The Authors. Journal of Ecology © 2011 British Ecological Society. |
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CIRAD, BP 4035, Libreville, Gabon |
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00220477 (Issn) |
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Cited By (since 1996): 1; Export Date: 23 October 2011; Source: Scopus; Coden: Jecoa; doi: 10.1111/j.1365-2745.2011.01829.x; Language of Original Document: English; Correspondence Address: Gourlet-Fleury, S.; Cirad, UR BandSEF, Biens et Services des Ecosystèmes Forestiers tropicaux, Campus International de Baillarguet, TA C-105/D, F-34398, Montpellier, France; email: sylvie.gourlet-fleury@cirad.fr |
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no |
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EcoFoG @ webmaster @ |
Serial |
361 |
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Author |
Dejean, A.; Delabie, J.H.C.; Cerdan, P.; Gibernau, M.; Corbara, B. |
Title |
Are myrmecophytes always better protected against herbivores than other plants? |
Type |
Journal Article |
Year |
2006 |
Publication |
Biological Journal of the Linnean Society |
Abbreviated Journal |
Biol. J. Linn. Soc. |
Volume |
89 |
Issue |
1 |
Pages |
91-98 |
Keywords |
Ant-plant mutualism; Azteca; Maieta; Myrmecophytes; Plant protection; Tococa; ant; defoliation; field method; mutualism; myrmecophyte; plant-herbivore interaction; Azteca; Azteca bequaerti; Clidemia; Crematogaster laevis; Formicidae; Maieta; Maieta guianensis; Pheidole minutula; Tococa; Tococa guianensis |
Abstract |
The present field study compared the degree of defoliation of three Guianian melastome, two myrmecophytes (i.e. plants sheltering ants in hollow structures) and Clidemia sp., a nonmyrmecophytic plant serving as a control. Maieta guianensis Aubl. hosted mostly Pheidole minutula Mayr whatever the area, whereas Tococa guianensis Aubl. hosted mostly Azteca bequaerti Wheeler along streams and Crematogaster laevis Mayr or Azteca sp. 1 in the understory where it never blossomed. Only Tococa, when sheltering A. bequaerti in what can be considered as a truly mutualistic relationship, showed significantly less defoliation than control plants. In the other associations, the difference was not significant, but P. minutula is mutualistic with Maieta because it furnishes some protection (exclusion experiments) plus nutrients (previous studies). When devoid of ants, Tococa showed significantly greater defoliation than control plants; therefore, it was deduced that Tococa probably lacks certain antidefoliator metabolites that control plants possess (both Tococa and control plants are protected by ground-nesting, plant-foraging ants, which is termed 'general myrmecological protection'). Consequently, plant-ants other than A. bequaerti probably also protect Tococa slightly, thus compensating for this deficiency and permitting it to live in the understory until treefall gaps provide the conditions necessary for seed production. © 2006 The Linnean Society of London. |
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Laboratoire de Psychologie Sociale de la Cognition (UMR CNRS 6024), Université Blaise Pascal, 34 avenue Carnot, 63037 Clermont-Ferrand Cedex, France |
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00244066 (Issn) |
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Cited By (since 1996): 9; Export Date: 22 October 2011; Source: Scopus; Coden: Bjlsb; doi: 10.1111/j.1095-8312.2006.00660.x; Language of Original Document: English; Correspondence Address: Dejean, A.; Laboratoire d'Evolution et Diversité Biologique (UMR CNRS 5174), Université Toulouse III, Bâtiment 4R3, 118 route de Narbonne, 31062 Toulouse Cedex, France; email: dejean@cict.fr |
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EcoFoG @ webmaster @ |
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355 |
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Gibernau, M.; Orivel, J.; Delabie, J.H.C.; Barabe, D.; Dejean, A. |
Title |
An asymmetrical relationship between an arboreal ponerine ant and a trash-basket epiphyte (Araceae) RID D-4390-2009 RID C-4034-2011 |
Type |
Journal Article |
Year |
2007 |
Publication |
Biological Journal of the Linnean Society |
Abbreviated Journal |
Biol. J. Linnean Soc. |
Volume |
91 |
Issue |
3 |
Pages |
341-346 |
Keywords |
hanging soil; mutualism; nest site selection; plant protection |
Abstract |
The relationship between ants and Philodendron insigne, a trash-basket epiphyte abundant along streams, was studied in French Guiana. Only a few (3%) of the young plants sheltered ants, whereas 90% of the mature individuals did. The most frequent associate was Odontomachus hastatus (Fabricius), an arboreal ponerine ant, and its nests were almost entirely (94.4%) located in P. insigne root clusters. Experimental choice tests conducted on O. hastatus workers confirmed their preference for P. insigne. We propose that the interactions between P. insigne and ants may be intermediate between non-obligatory, reward-based interactions and obligatory, specific ant-myrmecophyte interactions because (1) almost all mature P. insigne individuals are associated with ants; (2) O. hastatus is the most frequent when diverse ants nest in its root clusters; (3) ants colonize mature P. insigne, but rarely young individuals; (4) ants, particularly O. hastatus, protect the foliage of their host; and (5) at least one ant species, O. hastatus, prefers P. insigne over other host plants. The latter relationship is asymmetrical because P. insigne is inhabited by diverse ants whereas O. hastatus nests almost exclusively in P. insigne. (c) 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 341-346. |
Address |
Univ Toulouse 3, Lab Evolut & Divers Biol, UMR 5174, CNRS,UPS, F-31062 Toulouse 9, France, Email: dejean@cict.fr |
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Blackwell Publishing |
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English |
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0024-4066 |
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WOS:000247817100001 |
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no |
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EcoFoG @ webmaster @ |
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356 |
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Porth, I.; Scotti-Saintagne, C.; Barreneche, T.; Kremer, A.; Burg, K. |
Title |
Linkage mapping of osmotic stress induced genes of oak |
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Journal Article |
Year |
2005 |
Publication |
Tree Genetics and Genomes |
Abbreviated Journal |
Tree Genet. Genomes |
Volume |
1 |
Issue |
1 |
Pages |
31-40 |
Keywords |
Est; Linkage map; Oak; Osmotic stress; Quercus ssp.; Fagaceae; Quercus; Quercus petraea; Quercus robur |
Abstract |
Water stress affecting long-lived trees is an important challenge in forestry. Due to global climate change, forest trees will be threatened by extreme conditions like flooding or drought. It is necessary to understand differences in stress tolerance within certain species and to investigate putative relations on genomic level. In this study, osmotic stress induced genes of Quercus ssp. were positioned on two genetic linkage maps of oak. An intra-specific cross 3P*A4 of Quercus robur consisting of 88 offspring and an inter-specific cross 11P*QS29 of Q. robur and Q. petraea comprising 72 full-sibs were analyzed for the inheritance of 14 loci represented by 34 individual single nucleotide polymorphisms. Seven genes in the intra-cross, as well as other six genes in the inter-cross could be mapped and one gene could not be localised due to the severe distortion of the segregation. The collection of expressed sequences involved ribosomal proteins, members of the oxylase/oxygenase gene family, betaine aldehyde dehydrogenase, Dc3 promoter-binding factor, a putative member of the nodulin family, glutathione-S-transferase and proteins with unknown functions. In the inter-cross, two linked markers exhibited 89% deficiency of heterozygosity. Thirteen genes were positioned on ten different oak chromosomes and can serve as orthologous markers in comparative mapping studies within Fagaceae. © Springer-Verlag 2005. |
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INRA BIOGECO, 69 Route d'Arcachon, 33612 Cestas, France |
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16142942 (Issn) |
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Cited By (since 1996): 9; Export Date: 22 October 2011; Source: Scopus; doi: 10.1007/s11295-005-0005-1; Language of Original Document: English; Correspondence Address: Burg, K.; Division of Biogenetics and Natural Resources, Austrian Research Center Seibersdorf, 2444 Seibersdorf, Austria; email: kornel.burg@arcs.ac.at |
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EcoFoG @ webmaster @ |
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357 |
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Latouche-Hallé, C.; Ramboer, A.; Bandou, E.; Caron, H.; Kremer, A. |
Title |
Nuclear and chloroplast genetic structure indicate fine-scale spatial dynamics in a neotropical tree population |
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Journal Article |
Year |
2003 |
Publication |
Heredity |
Abbreviated Journal |
Heredity |
Volume |
91 |
Issue |
2 |
Pages |
181-190 |
Keywords |
Dicorynia guianensis; Gene flow; Genetic differentiation; Microsatellites; Spatial analysis; Tropical tree; gene flow; genetic structure; population genetics; spatial analysis; tree; tropical forest; Cell Nucleus; Chloroplasts; Cohort Studies; DNA, Plant; French Guiana; Genetic Markers; Pollen; Population Dynamics; Seeds; Trees; Variation (Genetics); French Guiana; Dicorynia guianensis; Embryophyta |
Abstract |
Dicorynia guianensis is a canopy tree, endemic to the tropical rain forest of French Guiana. We compared generational and spatial genetic structure for maternally and biparentally inherited markers in two cohorts (adult and seedling) in order to infer processes shaping the distribution of genetic diversity. The study was conducted on a 40 ha study plot located at Paracou near Kourou, where 172 adults trees and 375 saplings were sampled. Aggregation of trees was therefore suggested at different distances, ranging from 100 to 400 m. There was a strong link between demographic and genetic spatial structures at small distances (less than 100 m) that is likely to be the consequence of restricted seed dispersal. Genetic differentiation was more pronounced between spatial aggregates than between cohorts. Despite the spatial differentiation, the species was able to maintain high levels of diversity for maternal genomes, suggesting rapid turnover of aggregates. Spatial autocorrelation was larger for chloroplast than nuclear markers indicating a strong asymmetry between pollen and seed flow. Fixation indices indicated a lower heterozygote deficiency for the adults, maybe because of gradual elimination of selfed trees. Genetic relatedness at lower distances was higher in adult trees than in saplings, as a result of generation overlapping in the adult cohort. Overall, our results confirm earlier biological knowledge about the dispersion mechanisms of the species, and lead to an enhanced role of spatial processes in the dynamics of genetic diversity of D. guianensis. |
Address |
INRA Lab. Genet. Arbres Forestiers, BP45, 33611 Gazinet Cedex, France |
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0018067x (Issn) |
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Cited By (since 1996): 34; Export Date: 22 October 2011; Source: Scopus; Coden: Hdtya; doi: 10.1038/sj.hdy.6800296; PubMed ID: 12886285; Language of Original Document: English; Correspondence Address: Caron, H.; INRA Lab. Genet. Arbres Forestiers, BP45, 33611 Gazinet Cedex, France; email: caron@pierroton.inra.fr; Chemicals/CAS: DNA, Plant; Genetic Markers |
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EcoFoG @ webmaster @ |
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358 |
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Groc, S.; Delabie, J.H.C.; Cereghino, R.; Orivel, J.; Jaladeau, F.; Grangier, J.; Mariano, C.S.F.; Dejean, A. |
Title |
Ant species diversity in the 'Grands Causses' (Aveyron, France): In search of sampling methods adapted to temperate climates RID C-4034-2011 |
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Journal Article |
Year |
2007 |
Publication |
Comptes Rendus Biologies |
Abbreviated Journal |
C. R. Biol. |
Volume |
330 |
Issue |
12 |
Pages |
913-922 |
Keywords |
ant diversity; Grands Causses; sampling methods; temperate climate |
Abstract |
This study aimed at showing the applicability of using a combination of four sampling methods (i.e., Winkler extractors, pitfall traps, baiting and manual collection), something most often conducted in the tropics, to create an inventory of ant species diversity in temperate environments. We recorded a total of 33 ant species in the Grands Causses by comparing three vegetal formations: a steppic lawn ('causse' sensu stricto), which was the most species-rich (29 species), followed by an oak grove (22 species) and a pine forest (17 species). No sampling method alone is efficient enough to provide an adequate sampling, but their combination permits one to make a suitable inventory of the myrmecofauna and to obtain information on the ecology of these ant species. |
Address |
[Groc, S; Orivel, J; Grangier, J; Dejean, A] Univ Toulouse 3, CNRS, UMR 5174, Lab Evolut & Diversite Biol, F-31062 Toulouse, France, Email: alain.dejean@wanadoo.fr |
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Elsevier France-Editions Scientifiques Medicales Elsevier |
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English |
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1631-0691 |
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WOS:000251852800009 |
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EcoFoG @ webmaster @ |
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359 |
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Sharma, K.; Degen, B.; Von Wuehlisch, G.; Singh, N.B. |
Title |
Allozyme variation in eight natural populations of Pinus roxburghii Sarg. in India |
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Journal Article |
Year |
2002 |
Publication |
Silvae Genetica |
Abbreviated Journal |
Silvae Genet. |
Volume |
51 |
Issue |
5-6 |
Pages |
246-253 |
Keywords |
Allozymes; Differentiation; Genetic distance; Multilocus diversity; Pinus roxburghii; Variation; Enzymes; Forestry; Genes; Allozyme variations; Genetic engineering; Enzymes; Genes; Genetic Engineering; Pinus Roxburghii; Embryophyta; Pinus roxburghii |
Abstract |
Seeds collected from eight populations of Chir pine (Pinus roxburghii SARG.) from the natural distribution range of the species in Himachal Himalayas in India were analysed isozymatically at 11 enzyme systems. For the enzyme systems studied, 25 gene loci were identified out of which 18 were polymorphic. The observed mean values for genetic variation were slightly lower than mean values reported for Pinus species (number of alleles: 1.65 compared to 2.36; effective number of alleles: 1.13 compared to 1.26; observed heterozygosity: 0.153 compared to 0.179). A small differentiation among populations and large variation within populations were reflected by small value of GST (0.04): Considering the different genetic parameters three populations seem favourable for gene conservation measures. |
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Silviculture Division, Forest Research Institute, Dehra Dun – 248 006, India |
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00375349 (Issn) |
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Cited By (since 1996): 4; Export Date: 22 October 2011; Source: Scopus; Coden: Sigea; Language of Original Document: English; Correspondence Address: Sharma, K.; Dr. Y. S. Parmar Univ. Hort./Forest., Reg. Horticultural Research Station, Jachh (Nurpur)-176 201 (HP), India |
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EcoFoG @ webmaster @ |
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360 |
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Zhang, T.; Bai, S.-L.; Bardet, S.; Almeras, T.; Thibaut, B.; Beauchene, J. |
Title |
Radial variations of vibrational properties of three tropical woods |
Type |
Journal Article |
Year |
2011 |
Publication |
Journal of Wood Science |
Abbreviated Journal |
J. Wood Sci. |
Volume |
57 |
Issue |
5 |
Pages |
377-386 |
Keywords |
Damping coefficient; Dynamic modulus; Extractives; Microfibril angle; Tropical woods |
Abstract |
The radial trends of vibrational properties, represented by the specific dynamic modulus (E′/ρ) and damping coefficient (tan δ), were investigated for three tropical rainforest hardwood species (Simarouba amara, Carapa procera, and Symphonia globulifera) using free-free flexural vibration tests. The microfibril angle (MFA) was estimated using X-ray diffraction. Consistent patterns of radial variations were observed for all studied properties. E′/ρ was found to decrease from pith to bark, which was strongly related to the increasing pith-bark trend of MFA. The variation of tan δ along the radius could be partly explained by MFA and partly by the gradient of extractives due to heartwood formation. The coupling effect of MFA and extractives could be separated through analysis of the log(tan δ) versus log(E′/ρ) diagram. For the species studied, the extractive content putatively associated with heartwood formation generally tends to decrease the wood damping coefficient. However, this weakening effect of extractives was not observed for the inner part of the heartwood, suggesting that the mechanical action of extractives was reduced during their chemical ageing. © 2011 The Japan Wood Research Society. |
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CIRAD, UMR Ecofog, BP 701, 97387 Kourou Cedex, Guyane Française, France |
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14350211 (Issn) |
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Export Date: 26 October 2011; Source: Scopus; Coden: Jwscf; doi: 10.1007/s10086-011-1189-7; Language of Original Document: English; Correspondence Address: Bai, S.-L.; Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871, China; email: slbai@pku.edu.cn |
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EcoFoG @ webmaster @ |
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363 |
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