References of "Gorel, Anaïs"
     in
Bookmark and Share    
Full Text
See detailClimatic niche evolution within tropical tree lineages: the case of the Erythrophleum genus (Fabaceae - Caesalpinioideae) in Africa
Gorel, Anaïs ULiege

Doctoral thesis (2019)

In Africa, while some plant groups and specifically genera are strictly associated to specific biomes, evidence of widely distributed genera transcending biome or habitat boundaries have also been ... [more ▼]

In Africa, while some plant groups and specifically genera are strictly associated to specific biomes, evidence of widely distributed genera transcending biome or habitat boundaries have also been reported for herbaceous plants and for tree genera. In this thesis, we aim at understanding the evolutionary processes that allowed particular tropical tree lineages to adapt to contrasted environmental conditions and occur in vast areas. While a diversity of methods at different phylogenetic and spatial scales can provide complementary insights, detailed analyses of well-resolved clades are needed to build robust generalizations about niche evolution and biome shifts. Therefore, from species distribution modeling to hard physiological measurements, we attempt to disentangle the processes explaining the vast distribution of Erythrophleum (Fabaceae), a tropical tree genus widely distributed in Africa, Australia and China. A synthesis is first provided on the Erythrophleum species in Africa (Chapter 2). Erythrophleum encompasses two forest species and two savanna species. The forest species are morphologically similar and sold for timber under the same commercial name, Tali, but genetics revealed contrasted distribution. Erythrophleum ivorense is restricted to the wet coastal forest, while Erythrophleum suaveolens occurs over vast areas from the moist forest up to gallery forests in the savanna. Secondly, we use species distribution models to determine the bioclimatic constraints on the distribution of the Erythrophleum species and gene pools (Chapter 3). Our results support the substantial role of climate in niche evolution, and speciation, within the genus. Erythrophleum has managed to adapt to extremely contrasted climates, resulting in a distribution encompassing several biomes, from the wet forest to the dry forest and the savanna. Ecophysiological (Chapter 4) and experimental (Chapter 5) approaches are then used to get a functional understanding of the niche evolution within Erythrophleum. We find that, for the two forest species, the shift into drier environments was associated with a coordinated evolution of the xylem resistance to embolism, controlled by subtle adaptations in wood anatomical traits, and desiccation delay strategies at stem and leaf levels. Finally, after confronting our results with previous studies on congeneric species, we conclude that, for certain tree lineages, the lability of drought tolerance traits, specifically those related to xylem protection, is an important functional path allowing to transcend habitat and biome boundaries (Chapter 6). We then discuss the generalization of the niche evolution pattern we detected for Erythrophleum to other African genera. Comparing the niche of 1439 woody species at the continental scale, we provide new evidence supporting the niche evolution within many woody genera in tropical Africa (20% of the 532 studied genera). [less ▲]

Detailed reference viewed: 100 (15 ULiège)
Full Text
Peer Reviewed
See detailEcological niche divergence associated with species and populations differentiation in Erythrophleum (Fabaceae, Caesalpinioideae)
Gorel, Anaïs ULiege; Duminil, Jérôme; Doucet, Jean-Louis ULiege et al

in Plant Ecology and Evolution (2019)

Background and aims – The isolation of populations inside forest refugia during past climate changes has widely been hypothesized as a major driver of tropical plant diversity. Environmental conditions ... [more ▼]

Background and aims – The isolation of populations inside forest refugia during past climate changes has widely been hypothesized as a major driver of tropical plant diversity. Environmental conditions can also influence patterns of diversity by driving divergent selection leading to local adaptation and, potentially, ecological speciation. Genetic and phylogenetic approaches are frequently used to study the diversification of African tree clades. However, the environmental space occupied by closely related species or intra-specific gene pools is barely quantified, though needed to properly test hypotheses on diversification processes. Methods – Using species distribution models, we determined the bioclimatic constraints on the distribution of closely related species and intra-specific gene pools. Our study model, Erythrophleum (Fabaceae - Caesalpinioideae), is a tropical tree genus widespread across Africa, and vastly investigated for genetics. Here, we combined the available phylogenetic data with information on niche divergence to explore the role of ecology into diversification at the species and gene pool levels. Key results – Ecological speciation through climate has probably played a key role in the evolution of the Erythrophleum species. The differential climatic niche of the species indicated adaptive divergence along rainfall gradients, that have probably been boosted by past climate fluctuations. At the gene pool level, past climate changes during the Pleistocene have shaped genetic diversity, though within Erythrophleum suaveolens, adaptive divergence also occurred. Conclusions – We believe that ecological speciation is a key mechanism of diversification for tropical African tree species, since such climatic niche partition exist among many other genera. Modeling the environmental niche of closely related taxa, and testing for niche differentiation, combined with divergence dates offered new insights on the process of diversification. [less ▲]

Detailed reference viewed: 37 (13 ULiège)
Full Text
See detailQGIS 02 - Gestion des systèmes de coordonnées et projection dans QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Exercises to learn managing coordinate and projection systems in QGIS - Opensource Geographic Information System. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS ... [more ▼]

Exercises to learn managing coordinate and projection systems in QGIS - Opensource Geographic Information System. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and projection in QGIS, QGIS 03 - Table management in QGIS, QGIS 04 - Symbology management in QGIS, QGIS 05 - Layouts with QGIS, QGIS 06 - Digitizing vector layers with QGIS, QGIS 07 - GPS management and connection with QGIS, QGIS 08 - Georeferencing a raster file with QGIS, QGIS 09 - Geoprocessing in vector mode with QGIS, QGIS 10 - Geoprocessing in raster mode with QGIS, QGIS 11 - Using Web Services in QGIS. [less ▲]

Detailed reference viewed: 467 (216 ULiège)
Full Text
See detailQGIS 06 - Digitalisation de couches vectorielles avec QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Vector layer digitization exercises with QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate ... [more ▼]

Vector layer digitization exercises with QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and projection in QGIS, QGIS 03 - Table management in QGIS, QGIS 04 - Symbology management in QGIS, QGIS 05 - Layouts with QGIS, QGIS 06 - Digitizing vector layers with QGIS, QGIS 07 - GPS management and connection with QGIS, QGIS 08 - Geo-referencing a raster file with QGIS, QGIS 09 - Geoprocessing in vector mode with QGIS, QGIS 10 - Geoprocessing in raster mode with QGIS, QGIS 11 - Using Web Services in QGIS. [less ▲]

Detailed reference viewed: 309 (72 ULiège)
Full Text
See detailQGIS 11 - Utilisation de Web Services dans QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Exercices d'utilisation de Web Services dans QGIS - Système d'information géographique Opensource. Cette exercice fait partie d'une série d'exercices : QGIS 01 - Introduction générale à QGIS, QGIS 02 ... [more ▼]

Exercices d'utilisation de Web Services dans QGIS - Système d'information géographique Opensource. Cette exercice fait partie d'une série d'exercices : QGIS 01 - Introduction générale à QGIS, QGIS 02 - Gestion des systèmes de coordonnées et projection dans QGIS, QGIS 03 - Gestion des tables dans QGIS, QGIS 04 - Gestion de la symbologie dans QGIS, QGIS 05 - Les mises en page avec QGIS, QGIS 06 - Digitalisation de couches vectorielles avec QGIS, QGIS 07 - Gestion du GPS et connexion avec QGIS, QGIS 08 - Géoréférencement d'un fichier raster avec QGIS, QGIS 09 - Géotraitements en mode vectoriel avec QGIS, QGIS 10 - Géotraitements en mode raster avec QGIS, QGIS 11 - Utilisation de Web Services dans QGIS. [less ▲]

Detailed reference viewed: 213 (46 ULiège)
Full Text
See detailQGIS 01 - Introduction générale à QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Exercices d'introduction au logiciel QGIS - Système d'information géographique Opensource. Cette exercice fait partie d'une série d'exercices : QGIS 01 - Introduction générale à QGIS, QGIS 02 - Gestion ... [more ▼]

Exercices d'introduction au logiciel QGIS - Système d'information géographique Opensource. Cette exercice fait partie d'une série d'exercices : QGIS 01 - Introduction générale à QGIS, QGIS 02 - Gestion des systèmes de coordonnées et projection dans QGIS, QGIS 03 - Gestion des tables dans QGIS, QGIS 04 - Gestion de la symbologie dans QGIS, QGIS 05 - Les mises en page avec QGIS, QGIS 06 - Digitalisation de couches vectorielles avec QGIS, QGIS 07 - Gestion du GPS et connexion avec QGIS, QGIS 08 - Géoréférencement d'un fichier raster avec QGIS, QGIS 09 - Géotraitements en mode vectoriel avec QGIS, QGIS 10 - Géotraitements en mode raster avec QGIS, QGIS 11 - Utilisation de Web Services dans QGIS. [less ▲]

Detailed reference viewed: 459 (187 ULiège)
Full Text
See detailQGIS 03 - Gestion des tables dans QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Exercices to learn managing tables in QGIS - Opensource Geographic Information System. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system ... [more ▼]

Exercices to learn managing tables in QGIS - Opensource Geographic Information System. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and projection in QGIS, QGIS 03 - Table management in QGIS, QGIS 04 - Symbology management in QGIS, QGIS 05 - Layouts with QGIS, QGIS 06 - Digitizing vector layers with QGIS, QGIS 07 - GPS management and connection with QGIS, QGIS 08 - Georeferencing a raster file with QGIS, QGIS 09 - Geoprocessing in vector mode with QGIS, QGIS 10 - Geoprocessing in raster mode with QGIS, QGIS 11 - Using Web Services in QGIS. [less ▲]

Detailed reference viewed: 274 (59 ULiège)
Full Text
See detailQGIS 04 - Gestion de la symbologie dans QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Symbology management exercises in QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system ... [more ▼]

Symbology management exercises in QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and projection in QGIS, QGIS 03 - Table management in QGIS, QGIS 04 - Symbology management in QGIS, QGIS 05 - Layouts with QGIS, QGIS 06 - Digitizing vector layers with QGIS, QGIS 07 - GPS management and connection with QGIS, QGIS 08 - Georeferencing a raster file with QGIS, QGIS 09 - Geoprocessing in vector mode with QGIS, QGIS 10 - Geoprocessing in raster mode with QGIS, QGIS 11 - Using Web Services in QGIS. [less ▲]

Detailed reference viewed: 278 (75 ULiège)
Full Text
See detailQGIS 05 - Les mises en page avec QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Layout exercises with QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and ... [more ▼]

Layout exercises with QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and projection in QGIS, QGIS 03 - Table management in QGIS, QGIS 04 - Symbology management in QGIS, QGIS 05 - Layouts with QGIS, QGIS 06 - Digitizing vector layers with QGIS, QGIS 07 - GPS management and connection with QGIS, QGIS 08 - Georeferencing a raster file with QGIS, QGIS 09 - Geoprocessing in vector mode with QGIS, QGIS 10 - Geoprocessing in raster mode with QGIS, QGIS 11 - Using Web Services in QGIS. [less ▲]

Detailed reference viewed: 262 (68 ULiège)
Full Text
See detailQGIS 07 - Gestion du GPS et connexion avec QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Exercises to learn GPS management and connection with QGIS - Opensource Geographic Information System. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 ... [more ▼]

Exercises to learn GPS management and connection with QGIS - Opensource Geographic Information System. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and projection in QGIS, QGIS 03 - Table management in QGIS, QGIS 04 - Symbology management in QGIS, QGIS 05 - Layouts with QGIS, QGIS 06 - Digitizing vector layers with QGIS, QGIS 07 - GPS management and connection with QGIS, QGIS 08 - Georeferencing a raster file with QGIS, QGIS 09 - Geoprocessing in vector mode with QGIS, QGIS 10 - Geoprocessing in raster mode with QGIS, QGIS 11 - Using Web Services in QGIS. [less ▲]

Detailed reference viewed: 101 (25 ULiège)
Full Text
See detailQGIS 08 - Géoréférencement d'un fichier raster avec QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Exercises to learn georeferencing a raster file with QGIS - Opensource Geographic Information System. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 ... [more ▼]

Exercises to learn georeferencing a raster file with QGIS - Opensource Geographic Information System. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and projection in QGIS, QGIS 03 - Table management in QGIS, QGIS 04 - Symbology management in QGIS, QGIS 05 - Layouts with QGIS, QGIS 06 - Digitizing vector layers with QGIS, QGIS 07 - GPS management and connection with QGIS, QGIS 08 - Georeferencing a raster file with QGIS, QGIS 09 - Geoprocessing in vector mode with QGIS, QGIS 10 - Geoprocessing in raster mode with QGIS, QGIS 11 - Using Web Services in QGIS. [less ▲]

Detailed reference viewed: 114 (26 ULiège)
Full Text
See detailQGIS 09 - Géotraitements en mode vectoriel avec QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Geoprocessing exercises in vector mode with QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate ... [more ▼]

Geoprocessing exercises in vector mode with QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and projection in QGIS, QGIS 03 - Table management in QGIS, QGIS 04 - Symbology management in QGIS, QGIS 05 - Layouts with QGIS, QGIS 06 - Digitizing vector layers with QGIS, QGIS 07 - GPS management and connection with QGIS, QGIS 08 - Georeferencing a raster file with QGIS, QGIS 09 - Geoprocessing in vector mode with QGIS, QGIS 10 - Geoprocessing in raster mode with QGIS, QGIS 11 - Using Web Services in QGIS. [less ▲]

Detailed reference viewed: 216 (37 ULiège)
Full Text
See detailQGIS 10 - Géotraitements en mode raster avec QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege et al

Learning material (2019)

Geoprocessing exercises in raster mode with QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate ... [more ▼]

Geoprocessing exercises in raster mode with QGIS - Geographic Information System Opensource. This exercise is part of a series of exercises: QGIS 01 - General introduction to QGIS, QGIS 02 - Coordinate system management and projection in QGIS, QGIS 03 - Table management in QGIS, QGIS 04 - Symbology management in QGIS, QGIS 05 - Layouts with QGIS, QGIS 06 - Digitizing vector layers with QGIS, QGIS 07 - GPS management and connection with QGIS, QGIS 08 - Georeferencing a raster file with QGIS, QGIS 09 - Geoprocessing in vector mode with QGIS, QGIS 10 - Geoprocessing in raster mode with QGIS, QGIS 11 - Using Web Services in QGIS. [less ▲]

Detailed reference viewed: 176 (29 ULiège)
Full Text
Peer Reviewed
See detail11C-autoradiographs to image phloem loading
Hubeau, Michiel; Mincke, Jens; Vanhove, Christian et al

in Frontiers in Forests and Global Change (2019), 2:20

Detailed reference viewed: 21 (0 ULiège)
Full Text
Peer Reviewed
See detailA sharp floristic discontinuity revealed by the biogeographic regionalization of African savannas
Fayolle, Adeline ULiege; Swaine, Michael D.; Aleman, Julie et al

in Journal of Biogeography (2019)

Aim: In tropical Africa, savannas cover huge areas, have high plant species richness and are considered as a major natural resource for most countries. There is, however, little information available on ... [more ▼]

Aim: In tropical Africa, savannas cover huge areas, have high plant species richness and are considered as a major natural resource for most countries. There is, however, little information available on their floristics and biogeography at the continental scale, despite the importance of such information for our understanding of the drivers of species diversity at various scales and for effective conservation and management. Here, we collated and analysed floristic data from across the continent in order to propose a biogeographical regionalization for African savannas. Location: We collated floristic information (specifically woody species lists) for 298 samples of savanna vegetation across Africa, extending from 18° N to 33° S and from 17° W to 48° E. Taxa: We focused on native woody species. Methods: We used ordination and clustering to identify the floristic discontinuities and gradual transitions across African savannas. Floristic relationships, specificity and turnover, within and between floristic clusters, were analysed using a (dis‐)similarity‐ based approach. Results: We identified eight floristic clusters across African savannas which in turn were grouped into two larger macro‐units. Ordinations at species and genus levels showed a clear differentiation in woody species composition between the North/ West macro‐unit and the South/East macro‐unit. This floristic discontinuity matches to the High (i.e. N&W) and Low (S&E) division of Africa previously proposed by White (1983) and which tracks climatic and topographical variation. In the N&W savannas, the floristic gradient determined by rainfall was partitioned into the Sudanian (drier) and Guinean (wetter) clusters. Within the highly heterogeneous S&E savannas and woodlands, six clusters were identified: Ugandan, Ethiopian, Mozambican, Zambezian, Namibian and South African. Main conclusions: The proposed pan‐African classification of savannas and woodlands might assist the development of coordinated management and conservation policies. [less ▲]

Detailed reference viewed: 43 (11 ULiège)
Full Text
Peer Reviewed
See detailTesting the divergent adaptation of two congeneric tree species on a rainfall gradient using eco-physio-morphological traits
Gorel, Anaïs ULiege; Steppe, Kathy; Beeckman, Hans et al

in Biotropica (2019)

In tropical Africa, evidence of widely distributed genera transcending biomes or habitat boundaries has been reported. The evolutionary processes that allowed these lineages to disperse and adapt into new ... [more ▼]

In tropical Africa, evidence of widely distributed genera transcending biomes or habitat boundaries has been reported. The evolutionary processes that allowed these lineages to disperse and adapt into new environments are far from being resolved. To better understand these processes, we propose an integrated approach, based on the eco-physio-morphological traits of two sister species with adjacent distributions along a rainfall gradient. We used wood anatomical traits, plant hydraulics (vulnerability to cavitation, wood volumetric water content and hydraulic capacitance) and growth data from the natural habitat, in a common garden, to compare species with known phylogeny, very similar morphologically, but occupying contrasting habitats: Erythrophleum ivorense (wet forest) and Erythrophleum suaveolens (moist forest and forest gallery). We identified some slight differences in wood anatomical traits between the two species associated with strong differences in hydraulics, growth, and overall species distribution. The moist forest species, E. suaveolens had narrower vessels and intervessel pits, and higher vessel cell-wall reinforcement than E. ivorense. These traits allow a high resistance to cavitation and a continuous internal water supply of the xylem during water shortage, allowing a higher fitness during drought periods, but limiting growth. Our results confirm a trade-off between drought tolerance and growth, controlled by subtle adaptations in wood traits, as a key mechanism leading to the niche partitioning between the two Erythrophleum species. The generality of this trade-off and its importance in the diversification of the African tree flora remains to be tested. Our integrated eco-physio-morpho approach could be the way forward. [less ▲]

Detailed reference viewed: 18 (6 ULiège)
Full Text
See detailBiogeography and evolutionary ecology of the woody flora in tropical Africa
Fayolle, Adeline ULiege; Gorel, Anaïs ULiege; Swaine, Michael D. et al

Conference (2019)

Tropical forest and savanna are globally critical biomes and cover the overwhelming majority of the African continent. They support the lives of nearly a billion people, store a huge amount of carbon ... [more ▼]

Tropical forest and savanna are globally critical biomes and cover the overwhelming majority of the African continent. They support the lives of nearly a billion people, store a huge amount of carbon above- and below-ground, and host great biodiversity, including the iconic megafauna. The current extent of tropical forests and savannas, however, remains uncertain, because continental studies are based on remote-sensing products that often fail to distinguish tropical forests and savannas from intermediate vegetation states and in patchy landscapes. Here, we developed a very different approach based on the specific floristics of the forest and savanna biomes, using woody species lists from hundreds of sites scattered across Africa. We specifically propose a biome index based on species affinity to the forest or savanna biome that could be used in the future to predict the distribution of tropical forest and savanna following climate change scenario, or in the past to reconstruct past biomes using palynological or anthracological records. We additionally used the largest ever collation of georeferenced herbarium records made available by the RAINBIO project in association with our biome index, to delineate the distribution of tropical forest and savanna across Africa for circa 1400 tree and shrub species. This allowed us to propose a first map of biome specificity, entirely derived from floristic information, and that could be used as a base map for management and conservation, and specifically for the design of re- and af-forestation programs. Biome specificity was also examined across the phylogeny to identify clades associated with specific biome and environmental conditions, and clades transcending biomes. These results, combining information on species composition in specific sites and on species distribution from herbarium records, provided strong insights into the biogeography and evolutionary ecology of the woody flora in tropical Africa. [less ▲]

Detailed reference viewed: 88 (3 ULiège)
Full Text
Peer Reviewed
See detailComparative analysis of two sister Erythrophleum species (Leguminosae) reveal contrasting transcriptome-wide responses to early drought stress
Neji, M.; Gorel, Anaïs ULiege; Ojeda, D. I. et al

in Gene (2019), 694

With the ongoing climate change, African rainforests are expected to experience severe drought events in the future. In Africa, the tropical genus Erythrophleum (Fabaceae) includes two forest sister ... [more ▼]

With the ongoing climate change, African rainforests are expected to experience severe drought events in the future. In Africa, the tropical genus Erythrophleum (Fabaceae) includes two forest sister timber tree species displaying contrasting geographical distributions. Erythrophleum ivorense is adapted to wet evergreen Guineo-Congolian forests, whereas E. suaveolens occurs in a wider range of climates, being found in moist dense forests but also in gallery forests under a relatively drier climate. This geographical distribution pattern suggests that the two species might cope differently to drought at the genomic level. Yet, the genetic basis of tolerance response to drought stress in both species is still uncharacterized. To bridge this gap, we performed an RNA-seq approach on seedlings from each species to monitor their transcriptional responses at different levels of drought stress (0, 2 and 6 weeks after stopping watering seedlings). Monitoring of wilting symptoms revealed that E. suaveolens displayed an earlier phenotypic response to drought stress than E. ivorense. At the transcriptomic level, results revealed 2020 (1204 down-regulated/816 up-regulated) and 1495 differentially expressed genes (DEGs) in response to drought stress from a total of 67,432 and 66,605 contigs assembled in E. ivorense and E. suaveolens, respectively. After identifying 30,374 orthologs between species, we found that only 7 of them were DEGs shared between species, while 587 and 458 were differentially expressed only in E. ivorense or E. suaveolens, respectively. GO and KEGG enrichment analysis revealed that the two species differ in terms of significantly regulated pathways as well as the number and expression profile of DEGs (Up/Down) associated with each pathway in the two stress stages. Our results suggested that the two studied species react differently to drought. E. suaveolens seems displaying a prompt response to drought at its early stage strengthened by the down-regulation of many DEGs encoding for signaling and metabolism-related pathways. A considerable up-regulation of these pathways was also found in E. ivorense at the late stage of drought, suggesting this species may be a late responder. Overall, our data may serve as basis for further understanding the genetic control of drought tolerance in tropical trees and favor the selection of crucial genes for genetically enhancing drought resistance. © 2019 Elsevier B.V. [less ▲]

Detailed reference viewed: 67 (13 ULiège)
Full Text
Peer Reviewed
See detailBanque de graines du sol et déterminants de la germination du tali, Erythrophleum suaveolens (Guill. & Perr.) Brenan
Douh, Chauvelin ULiege; Gorel, Anaïs ULiege; Daïnou, Kasso ULiege et al

in Bois et Forêts des Tropiques (2018), 338

Cette étude évalue l’abondance des graines d’Erythrophleum suaveolens dans la banque du sol des forêts denses humides d’Afrique centrale. Les travaux ont été menés au Nord-Congo dans deux types forestiers ... [more ▼]

Cette étude évalue l’abondance des graines d’Erythrophleum suaveolens dans la banque du sol des forêts denses humides d’Afrique centrale. Les travaux ont été menés au Nord-Congo dans deux types forestiers : la forêt à Celtis sur des sols argilo-sableux à sablo-argileux et la forêt à Manilkara sur des sols sableux. Les tiges d’E. suaveolens (dhp ≥ 10 cm) ont été inventoriées dans deux parcelles de 400 ha, et les structures diamétriques de leurs populations ont été comparées. En outre, 80 fosses (2 x 40 fosses par type de forêt) ont été creusées aux pieds de 20 arbres (10 par forêt), sur trois couches contiguës de 10 cm chacune, soit à une profondeur totale de 30 cm, et l’abondance des graines dans la banque du sol a été évaluée. La dormance des graines récoltées a été testée par des essais de germination après traitement au H2SO4 et cinq graines prélevées jusqu’à une profondeur de 20 cm dans la forêt à Celtis ont été utilisées pour estimer leur âge par Spectroscopie de Masse par Accélérateur (SMA). La comparaison des structures diamétriques indique une plus grande proportion de tiges de faible diamètre dans la forêt à Celtis. Alors que les densités de tiges (dhp ≥ 10 cm) sont proches, avec 0,85 et 1,05 tige/ha respectivement, dans la forêt à Celtis et la forêt à Manilkara, les densités de graines sont significativement plus élevées dans la forêt à Celtis (8,55 graines/m2) que dans la forêt à Manilkara (0,15 graine/m2). Le pourcentage maximum de germination obtenu était de 19,1 % pour des graines n’ayant subi aucun traitement. Les lots traités à l’acide ont présenté de moindres taux de germination. Ces graines pourraient se conserver une dizaine d’années dans la banque du sol. Les facteurs pouvant influencer les variations de densité des graines sont discutés et des recommandations sylvicoles sont formulées. [less ▲]

Detailed reference viewed: 67 (12 ULiège)
Full Text
See detailIntroduction générale à QGIS
Lejeune, Philippe ULiege; Gorel, Anaïs ULiege; Dupuis, Chloé ULiege

Learning material (2018)

Exercices d'introduction au logiciel QGIS - Système d'information géographique Opensource

Detailed reference viewed: 82 (11 ULiège)