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Author Maréchaux, I.; Bonal, D.; Bartlett, M.K.; Burban, B.; Coste, S.; Courtois, E.A.; Dulormne, M.; Goret, J.-Y.; Mira, E.; Mirabel, A.; Sack, L.; Stahl, C.; Chave, J. url  doi
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  Title Dry-season decline in tree sapflux is correlated with leaf turgor loss point in a tropical rainforest Type Journal Article
  Year 2018 Publication Functional Ecology Abbreviated Journal Funct Ecol  
  Volume 32 Issue 10 Pages 2285-2297  
  Keywords drought tolerance; hydraulic conductance; sap flow; sapflux density; tropical trees; turgor loss point; water potential; wilting point  
  Abstract Water availability is a key determinant of forest ecosystem function and tree species distributions. While droughts are increasing in frequency in many ecosystems, including in the tropics, plant responses to water supply vary with species and drought intensity and are therefore difficult to model. Based on physiological first principles, we hypothesized that trees with a lower turgor loss point (pi-tlp), that is, a more negative leaf water potential at wilting, would maintain water transport for longer into a dry season. We measured sapflux density of 22 mature trees of 10 species during a dry season in an Amazonian rainforest, quantified sapflux decline as soil water content decreased and tested its relationship to tree pi-tlp, size and leaf predawn and midday water potentials measured after the onset of the dry season. The measured trees varied strongly in the response of water use to the seasonal drought, with sapflux at the end of the dry season ranging from 37 to 117% (on average 83 +/- 5 %) of that at the beginning of the dry season. The decline of water transport as soil dried was correlated with tree pi-tlp (Spearman's rho > 0.63), but not with tree size or predawn and midday water potentials. Thus, trees with more drought-tolerant leaves better maintained water transport during the seasonal drought. Our study provides an explicit correlation between a trait, measurable at the leaf level, and whole-plant performance under drying conditions. Physiological traits such as pi-tlp can be used to assess and model higher scale processes in response to drying conditions.  
  Address  
  Corporate Author Thesis  
  Publisher Wiley/Blackwell (10.1111) Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0269-8463 ISBN Medium  
  Area Expedition Conference  
  Notes doi: 10.1111/1365-2435.13188 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 830  
Permanent link to this record
 

 
Author Coste, S.; Roggy, J.C.; Imbert, P.; Born, C.; Bonal, D.; Dreyer, E. openurl 
  Title Leaf photosynthetic traits of 14 tropical rain forest species in relation to leaf nitrogen concentration and shade tolerance Type Journal Article
  Year 2005 Publication Tree Physiology Abbreviated Journal Tree Physiol.  
  Volume 25 Issue 9 Pages 1127-1137  
  Keywords functional diversity; leaf carbon; leaf nitrogen; nitrogen-use efficiency; photosynthetic capacity; tropical rain forest  
  Abstract Variability of leaf traits related to photosynthesis was assessed in seedlings from 14 tree species growing in the tropical rain forest of French Guiana. Leaf photosynthetic capacity (maximum rate of carboxylation and maximum rate of electron transport) was estimated by fitting a biochemical model of photosynthesis to response curves of net CO2 assimilation rate versus intercellular CO2 mole fraction. Leaf morphology described by leaf mass per unit leaf area (LMA), density and thickness, as well as area- and mass-based nitrogen (N) and carbon (C) concentrations, were recorded on the same leaves. Large interspecific variability was detected in photosynthetic capacity as well as in leaf structure and leaf N and C concentrations. No correlation was found between leaf thickness and density. The correlations between area- and mass-based leaf N concentration and photosynthetic capacity were poor. Conversely, the species differed greatly in relative N allocation to carboxylation and bioenergetics. Principal component analysis (PCA) revealed that, of the recorded traits, only the computed fraction of total leaf N invested in photosynthesis was tightly correlated to photosynthetic capacity. We also used PCA to test to what extent species with similar shade tolerances displayed converging leaf traits related to photosynthesis. No clear-cut ranking could be detected among the shade-tolerant groups, as confirmed by a one-way ANOVA. We conclude that the large interspecific diversity in photosynthetic capacity was mostly explained by differences in the relative allocation of N to photosynthesis and not by leaf N concentration, and that leaf traits related to photosynthetic capacity did not discriminate shade-tolerance ranking of these tropical tree species.  
  Address CNRS Ecol Forets Guyane, INRA, ENGREF,CIRAD, Unite Mixte Rech, Kourou 97387, French Guiana, Email: roggy.j@cirad.fr  
  Corporate Author Thesis  
  Publisher HERON PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0829-318X ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000231555200005 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 230  
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Author Cochard, H.; Coste, S.; Chanson, B.; Guehl, J.M.; Nicolini, E. openurl 
  Title Hydraulic architecture correlates with bud organogenesis and primary shoot growth in beech (Fagus sylvatica) Type Journal Article
  Year 2005 Publication Tree Physiology Abbreviated Journal Tree Physiol.  
  Volume 25 Issue 12 Pages 1545-1552  
  Keywords development; hydraulic conductance; leaf primordia; meristem; xylem  
  Abstract In beech (Fagus sylvatica L.), the number of leaf primordia preformed in the buds determines the length and the type (long versus short) of annual growth units, and thus, branch growth and architecture. We analyzed the correlation between the number of leaf primordia and the hydraulic conductance of the vascular system connected to the buds. Terminal buds of short growth units and axillary buds of long growth units on lower branches of mature trees were examined. Buds with less than four and more than five leaf primordia formed short and long growth units, respectively. Irrespective of the type of growth unit the bud was formed on, the occurrence of a large number of leaf primordia was associated with high xylem hydraulic conductance. Xylem conductance was correlated to the area of the outermost annual ring. These results suggest that organogenesis and primary growth in buds correlates with secondary growth of the growth units and thus with their hydraulic architecture. Possible causal relationships between the variables are discussed.  
  Address INRA UBP, UMR PIAF, F-63039 Clermont Ferrand, France, Email: cochard@clermont.inra.fr  
  Corporate Author Thesis  
  Publisher HERON PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0829-318X ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000234019900008 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 281  
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Author Coste, S.; Baraloto, C.; Leroy, C.; Marcon, E.; Renaud, A.; Richardson, A.D.; Roggy, J.C.; Schimann, H.; Uddling, J.; Herault, B. openurl 
  Title Assessing foliar chlorophyll contents with the SPAD-502 chlorophyll meter: a calibration test with thirteen tree species of tropical rainforest in French Guiana Type Journal Article
  Year 2010 Publication Annals of Forest Science Abbreviated Journal Ann. For. Sci.  
  Volume 67 Issue 6 Pages 607  
  Keywords chlorophyll estimate; model calibration; homographic functions; neotropical trees  
  Abstract Chlorophyll meters such as the SPAD-502 offer a simple, inexpensive and rapid method to estimate foliar chlorophyll content. However, values provided by SPAD-502 are unitless and require empirical calibrations between SPAD units and extracted chlorophyll values. Leaves of 13 tree species from the tropical rain forest in French Guiana were sampled to select the most appropriate calibration model among the often-used linear, polynomial and exponential models, in addition to a novel homographic model that has a natural asymptote. The homographic model best accurately predicted total chlorophyll content (mu g cm(-2)) from SPAD units (R-2 = 0.89). Interspecific differences in the homographic model parameters explain less than 7% of the variation in chlorophyll content in our data set. The utility of the general homographic model for a variety of research and management applications clearly outweighs the slight loss of model accuracy due to the abandon of the species' effect.  
  Address [Herault, Bruno] Univ Antilles Guyane, Unite Mixte Rech Ecol Forets Guyane, Kourou, France, Email: bruno.herault@ecofog.gf  
  Corporate Author Thesis  
  Publisher EDP SCIENCES S A Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1286-4560 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000282350300007 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 40  
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Author Coste, S.; Roggy, J.C.; Garraud, L.; Heuret, P.; Nicolini, E.; Dreyer, E. openurl 
  Title Does ontogeny modulate irradiance-elicited plasticity of leaf traits in saplings of rain-forest tree species? A test with Dicorynia guianensis and Tachigali melinonii (Fabaceae, Caesalpinioideae) Type Journal Article
  Year 2009 Publication Annals of Forest Science Abbreviated Journal Ann. For. Sci.  
  Volume 66 Issue 7 Pages 701-709  
  Keywords plant architecture; phenotypic plasticity; photosynthetic capacity; leaf structure; tropical rain forest  
  Abstract Irradiance elicits a large plasticity in leaf traits, but little is known about the modulation of this plasticity by ontogeny. Interactive effects of relative irradiance and ontogeny were assessed on leaf traits for two tropical rainforest tree species: Dicorynia guianensis Amshoff and Tachigali melinonii (Harms) Barneby (Fabaceae, Caesalpinioideae). Eleven morphological and physiological leaf traits, relative to photosynthetic performance, were measured on saplings at three different architectural development stages (ASD 1, 2 and 3) and used to derive composite traits like photosynthetic N-use efficiency. Measurements were made along a natural irradiance gradient. The effect of ASD was very visible and differed between the two species. For Dicorynia guianensis, only leaf mass-per-area (LMA) significantly increased with ASDs whereas for Tachigali melinonii, almost all traits were affected by ASD: LMA, leaf N content and photosynthetic capacity increased from ASD 1 to ASD 3. Photosynthetic N-use-efficiency was not affected by ASD in any species. Leaf traits were severely modulated by irradiance, whereas the degree of plasticity was very similar among ASDs. Only few interactions were detected between irradiance and ASD, for leaf thickness, carbon content, and the ratio Chl/N in T. melinonii and for photosynthetic capacity in D. guianensis. We conclude that ontogenic development and irradiance-elicited plasticity modulated leaf traits, with almost no interaction, i.e., the degree of irradiance-elicited plasticity was stable across development stages and independent of ontogeny in these two species, at least in the early stages of development assessed here.  
  Address [Dreyer, Erwin] INRA, UMR Ecol & Ecophysiol Forestieres 1137, F-54280 Champenoux, France, Email: dreyer@nancy.inra.fr  
  Corporate Author Thesis  
  Publisher EDP SCIENCES S A Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1286-4560 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000270906600009 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 100  
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