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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 0829-318X ISBN Medium  
  Area (up) Expedition Conference  
  Notes ISI:000234019900008 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 281  
Permanent link to this record
 

 
Author Coste, S.; Roggy, J.C.; Schimann, H.; Epron, D.; Dreyer, E. pdf  openurl
  Title A cost-benefit analysis of acclimation to low irradiance in tropical rainforest tree seedlings: leaf life span and payback time for leaf deployment Type Journal Article
  Year 2011 Publication Journal of Experimental Botany Abbreviated Journal J. Exp. Bot.  
  Volume 62 Issue 11 Pages 3941-3955  
  Keywords Carbon balance; construction cost; functional diversity; leaf life span; payback time; photosynthesis; tropical rainforest  
  Abstract The maintenance in the long run of a positive carbon balance under very low irradiance is a prerequisite for survival of tree seedlings below the canopy or in small gaps in a tropical rainforest. To provide a quantitative basis for this assumption, experiments were carried out to determine whether construction cost (CC) and payback time for leaves and support structures, as well as leaf life span (i) differ among species and (ii) display an irradiance-elicited plasticity. Experiments were also conducted to determine whether leaf life span correlates to CC and payback time and is close to the optimal longevity derived from an optimization model. Saplings from 13 tropical tree species were grown under three levels of irradiance. Specific-CC was computed, as well as CC scaled to leaf area at the metamer level. Photosynthesis was recorded over the leaf life span. Payback time was derived from CC and a simple photosynthesis model. Specific-CC displayed only little interspecific variability and irradiance-elicited plasticity, in contrast to CC scaled to leaf area. Leaf life span ranged from 4 months to > 26 months among species, and was longest in seedlings grown under lowest irradiance. It was always much longer than payback time, even under the lowest irradiance. Leaves were shed when their photosynthesis had reached very low values, in contrast to what was predicted by an optimality model. The species ranking for the different traits was stable across irradiance treatments. The two pioneer species always displayed the smallest CC, leaf life span, and payback time. All species displayed a similar large irradiance-elicited plasticity.  
  Address [Coste, S; Epron, D; Dreyer, E] INRA, UMR1137, Ctr INRA Nancy, F-54280 Champenoux, France, Email: dreyer@nancy.inra.fr  
  Corporate Author Thesis  
  Publisher Oxford Univ Press Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-0957 ISBN Medium  
  Area (up) Expedition Conference  
  Notes WOS:000292838700021 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 331  
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Author Leroy, C.; Gril, E.; Si Ouali, L.; Coste, S.; Gérard, B.; Maillard, P.; Mercier, H.; Stahl, C. url  doi
openurl 
  Title Water and nutrient uptake capacity of leaf-absorbing trichomes vs. roots in epiphytic tank bromeliads Type Journal Article
  Year 2019 Publication Environmental and Experimental Botany Abbreviated Journal Environ. Exp. Bot.  
  Volume 163 Issue Pages 112-123  
  Keywords 15 N labelling; Carbon metabolism; Nutrient uptake; Plant performance; Tank bromeliad; Water status; Aechmea  
  Abstract The water and nutrient uptake mechanisms used by vascular epiphytes have been the subject of a few studies. While leaf absorbing trichomes (LATs) are the main organ involved in resource uptake by bromeliads, little attention has been paid to the absorbing role of epiphytic bromeliad roots. This study investigates the water and nutrient uptake capacity of LATs vs. roots in two epiphytic tank bromeliads Aechmea aquilega and Lutheria splendens. The tank and/or the roots of bromeliads were watered, or not watered at all, in different treatments. We show that LATs and roots have different functions in resource uptake in the two species, which we mainly attributed to dissimilarities in carbon acquisition and growth traits (e.g., photosynthesis, relative growth rate, non-structural carbohydrates, malate), to water relation traits (e.g., water and osmotic potentials, relative water content, hydrenchyma thickness) and nutrient uptake (e.g., 15 N-labelling). While the roots of A. aquilega did contribute to water and nutrient uptake, the roots of L. splendens were less important than the role played by the LATs in resource uptake. We also provide evidenced for a synergistic effect of combined watering of tank and root in the Bromelioideae species. These results call for a more complex interpretation of LATs vs. roots in resource uptake in bromeliads. © 2019 Elsevier B.V.  
  Address INRA, UMR EcoFoG, CNRS, CIRAD, AgroParisTech, Université des Antilles, Université de Guyane, Kourou, 97310, France  
  Corporate Author Thesis  
  Publisher Elsevier B.V. Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 00988472 (Issn) ISBN Medium  
  Area (up) Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 871  
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Author Biwolé, A.B.; Dainou, K.; Fayolle, A.; Hardy, O.J.; Brostaux, Y.; Coste, S.; Delion, S.; Betti, J.L.; Doucet, J.-L. doi  openurl
  Title Light Response of Seedlings of a Central African Timber Tree Species, Lophira alata (Ochnaceae), and the Definition of Light Requirements Type Journal Article
  Year 2015 Publication Biotropica Abbreviated Journal Biotropica  
  Volume 47 Issue 6 Pages 681-688  
  Keywords biomass allocation; Central Africa; light requirement: Lophira alata; population; relative growth rate; seedling growth; timber species; Afrique centrale; allocation de biomasse; besoins en lumière; croissance des semis; bois d'œuvre; Lophira alata; population; taux de croissance relatif  
  Abstract Light is of primary importance in structuring tropical tree communities. Light exposure at seedling and adult stages has been used to characterize the ecological profile of tropical trees, with many implications in forest management and restoration ecology. Most shade-tolerance classification systems have been proposed based on empirical observations in a specific area and thus result in contradictions among categories assigned to a given species. In this study, we aimed to quantify the light requirements for seedling growth of a Central African timber tree, Lophira alata (Ochnaceae), taking into account effects of population origin. In two controlled experiments: a light response experiment and a comparative population experiment, conducted in southwestern Cameroon, using seeds collected from four populations (three from Cameroon and one from Gabon), we examined the quantitative responses to irradiance of seedlings. After 2 years, mortality was very low (<3%), even in extremely low irradiance. Growth and biomass allocation patterns varied in response to light, with intermediate irradiance (24–43%) providing optimal conditions. Light response differed between populations. The Boumba population in the northeastern edge of the species' distribution exhibited the highest light requirements, suggesting a local adaptation. As a result of positive growth at low irradiance and maximum growth at intermediate irradiance, we concluded that L. alata exhibits characteristics of both non-pioneer and pioneer species. Implications of our results to propose an objective way to assign the light requirement for tropical tree species are discussed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1744-7429 ISBN Medium  
  Area (up) Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 648  
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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
openurl 
  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 0269-8463 ISBN Medium  
  Area (up) Expedition Conference  
  Notes doi: 10.1111/1365-2435.13188 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 830  
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