Carbon isotope composition, gas exchange and heterotrophy in autralian mistletoes / J.D. Marshall (1994)

Public ISBD Titre : Carbon isotope composition, gas exchange and heterotrophy in autralian mistletoes Type de document : texte imprimé Auteurs : J.D. Marshall, Auteur ; J.R. Ehleringer, Auteur ; Ernst-Detlef Schulze, Auteur ; G. Farquhar, Auteur Année de publication : 1994 Importance : pp. 237-241 Présentation : graph., tabl., réf. Note générale : Extrait de Functional Ecology - Vol.8 - n°2 Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Carbone ; Photosynthèse ; Transpiration ; Australie ; Xylème ; Sève ; Acacia Résumé : Photosynthesis, transpiration and carbon isotope ratios of 11 mistletoes and their hosts were measured in central and eastern Australia to test hypotheses regarding similarity of photosynthetic rate between host and parasite and significance of host xylem carbon as a contributor to parasite carbon gain. Differences in photosynthetic rates of mistletoes and their hosts were not statistically significant, although most mistletoes had slightly lower photosynthetic rates and much higher transpiration rates than their hosts. Uptake of carbon dissolved in the xylem sap of the host was estimated from the discrepancy between observed and predicted carbon isotope ratios. Dividing xylem carbon gain by measured transpiration yielded a mean ± SE xylem carbon concentration of 10 ± 2.0 mM (...) Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=148704 Carbon isotope composition, gas exchange and heterotrophy in autralian mistletoes [texte imprimé] / J.D. Marshall, Auteur ; J.R. Ehleringer, Auteur ; Ernst-Detlef Schulze, Auteur ; G. Farquhar, Auteur . - 1994 . - pp. 237-241 : graph., tabl., réf. Extrait de Functional Ecology - Vol.8 - n°2 Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Carbone ; Photosynthèse ; Transpiration ; Australie ; Xylème ; Sève ; Acacia Résumé : Photosynthesis, transpiration and carbon isotope ratios of 11 mistletoes and their hosts were measured in central and eastern Australia to test hypotheses regarding similarity of photosynthetic rate between host and parasite and significance of host xylem carbon as a contributor to parasite carbon gain. Differences in photosynthetic rates of mistletoes and their hosts were not statistically significant, although most mistletoes had slightly lower photosynthetic rates and much higher transpiration rates than their hosts. Uptake of carbon dissolved in the xylem sap of the host was estimated from the discrepancy between observed and predicted carbon isotope ratios. Dividing xylem carbon gain by measured transpiration yielded a mean ± SE xylem carbon concentration of 10 ± 2.0 mM (...) Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=148704

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Carbon isotope ratios of plants of a tropical dry forest in Mexico / Harold A (1932-....). Mooney (1989)

Public ISBD Titre : Carbon isotope ratios of plants of a tropical dry forest in Mexico Type de document : texte imprimé Auteurs : Harold A (1932-....). Mooney, Auteur ; S.H. Bullock, Auteur ; J.R. Ehleringer, Auteur Année de publication : 1989 Importance : pp. 137-142 Présentation : réf. Note générale : Extrait de Functional Ecology - Vol.3 - n°2 Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Amérique centrale ; Forêt ; Photosynthèse ; Habitat ; Carbone ; Mexique ; Utilisation de l'eau Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=149788 Carbon isotope ratios of plants of a tropical dry forest in Mexico [texte imprimé] / Harold A (1932-....). Mooney, Auteur ; S.H. Bullock, Auteur ; J.R. Ehleringer, Auteur . - 1989 . - pp. 137-142 : réf. Extrait de Functional Ecology - Vol.3 - n°2 Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Amérique centrale ; Forêt ; Photosynthèse ; Habitat ; Carbone ; Mexique ; Utilisation de l'eau Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=149788

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CO2 concentration profiles, and carbon and oxygen isotopes in C3 and C4 crop canopies / N. Buchmann (1998)

Public ISBD Titre : CO2 concentration profiles, and carbon and oxygen isotopes in C3 and C4 crop canopies Type de document : texte imprimé Auteurs : N. Buchmann, Auteur ; J.R. Ehleringer, Auteur Editeur : Elsevier Année de publication : 1998 Importance : pp.45-58 Présentation : graph., réf. Note générale : Extrait d'Agricultural and Forest Meteorology - Vol.89 - n°1 Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Medicago sativa ; Festuca ; Carbone ; Isotope ; Sol ; Maïs Résumé : CO2 concentrations ([CO2]), as well as carbon and oxygen isotope ratios (δ13C, δ18O) were measured within alfalfa (C3) and corn (C4) crop canopies (leaf area indices of 4.6 and 2.5, respectively). Daily fluctuations were observed within the canopy and extended into the canopy boundary layer (at heights 2 to 3 times higher than the maximum plant height). Photosynthetic demand for canopy CO2 exceeded soil respiration to such an extent that daytime [CO2] values were depleted 15 to 50 ppm below tropospheric values; δ13C values of canopy air reached a maximum of 3‰ heavier than the tropospheric baseline values. Highly significant relationships were observed between δ13C and δ18O ratios of canopy air in both crop canopies. Leaf carbon isotope discrimination was significantly different between species, 20‰ (alfalfa) vs. 4‰ (corn). However, the relationships between 1/[CO2] and δ13C, as well as 1/[CO2] and δ18O of canopy air did not differ between the two crop species. Thus, ecosystem respiration had an average δ13C ratio of −21.6‰ and a δ18O ratio of 29‰. The δ13C values of soil-respired CO2 were similar in both C3 and C4 crop stands (approximately −22.6‰). Ecosystem-level carbon isotope discrimination (Δe) estimates were indistinguishable between both crops (13.8‰ for alfalfa, and 13.2‰ for corn). Thus, the Δe estimates, as well as the δ13C values of soil organic carbon and soil-respired CO2 integrate 13C contributions from the current standing plant cover, as well as from crops of previous years in this crop rotation system. Furthermore, this study clearly indicated that the carbon isotope ratios of carbon fixed and carbon released were not near the equilibrium values expected for the current crop at each site. The implications of this isotopic disequilibrium of a crop rotation agricultural system are discussed with respect to scaling canopy-level observations to global models for identifying C sinks. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=149715 CO2 concentration profiles, and carbon and oxygen isotopes in C3 and C4 crop canopies [texte imprimé] / N. Buchmann, Auteur ; J.R. Ehleringer, Auteur . - [S.l.] : Elsevier, 1998 . - pp.45-58 : graph., réf. Extrait d'Agricultural and Forest Meteorology - Vol.89 - n°1 Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Medicago sativa ; Festuca ; Carbone ; Isotope ; Sol ; Maïs Résumé : CO2 concentrations ([CO2]), as well as carbon and oxygen isotope ratios (δ13C, δ18O) were measured within alfalfa (C3) and corn (C4) crop canopies (leaf area indices of 4.6 and 2.5, respectively). Daily fluctuations were observed within the canopy and extended into the canopy boundary layer (at heights 2 to 3 times higher than the maximum plant height). Photosynthetic demand for canopy CO2 exceeded soil respiration to such an extent that daytime [CO2] values were depleted 15 to 50 ppm below tropospheric values; δ13C values of canopy air reached a maximum of 3‰ heavier than the tropospheric baseline values. Highly significant relationships were observed between δ13C and δ18O ratios of canopy air in both crop canopies. Leaf carbon isotope discrimination was significantly different between species, 20‰ (alfalfa) vs. 4‰ (corn). However, the relationships between 1/[CO2] and δ13C, as well as 1/[CO2] and δ18O of canopy air did not differ between the two crop species. Thus, ecosystem respiration had an average δ13C ratio of −21.6‰ and a δ18O ratio of 29‰. The δ13C values of soil-respired CO2 were similar in both C3 and C4 crop stands (approximately −22.6‰). Ecosystem-level carbon isotope discrimination (Δe) estimates were indistinguishable between both crops (13.8‰ for alfalfa, and 13.2‰ for corn). Thus, the Δe estimates, as well as the δ13C values of soil organic carbon and soil-respired CO2 integrate 13C contributions from the current standing plant cover, as well as from crops of previous years in this crop rotation system. Furthermore, this study clearly indicated that the carbon isotope ratios of carbon fixed and carbon released were not near the equilibrium values expected for the current crop at each site. The implications of this isotopic disequilibrium of a crop rotation agricultural system are discussed with respect to scaling canopy-level observations to global models for identifying C sinks. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=149715

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Comparisons of carbon isotope discrimination in populations of aridland plant species differing in lifespan / W.S.F. Schuster (1992)

Public ISBD Titre : Comparisons of carbon isotope discrimination in populations of aridland plant species differing in lifespan Type de document : texte imprimé Auteurs : W.S.F. Schuster, Auteur ; D.R. Sandquist, Auteur ; S.L. Philips, Auteur ; J.R. Ehleringer, Auteur Année de publication : 1992 Importance : pp. 332-337 Présentation : graph., réf. Note générale : Extrait d'Oecologia - Vol.91 - n°3 Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Communauté végétale ; Désert ; Isotope ; Carbone ; Phytoécologie ; Potentiel hydrique ; Relation plante eau Résumé : Carbon isotope discrimination (Delta) was compared between populations of dominant perennial plant species, differing in life expectancy, in two deserts with contrasting vegetation types. In both deserts, plants of the shorter-lived species showed significantly higher Delta and greater intrapopulation variance in this character compared to the long-lived species. These results indicate underlying differences in gas-exchange physiology, and suggest a positive correlation between water-use efficiency and lifespan in desert plants. Differences in variance for this character may reflect greater microenvironmental variation experienced by shorter-lived plants and/or different forms of selection acting on water-use traits. Spatial distributions were significantly clustered for the shorter-lived species and significantly uniform for the long-lived species, indicating that competition has been important in the development of the long-lived populations. The long-lived Larrea tridentata showed a significant, negative correlation between Delta and Thiessen polygon area, suggesting a positive relationship between water-use efficiency and longevity within this species. This relationship was weakly supported in the other warm desert species, Encelia farinosa, but was not observed within populations of the cold desert species, Gutierrezia microcephala and Coleogyne ramosissima. These results suggest that Delta reflects key aspects of plant metabolism related to lifespan; these differences may ultimately influence interactions among desert plants and the structure of desert plant communities. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=146982 Comparisons of carbon isotope discrimination in populations of aridland plant species differing in lifespan [texte imprimé] / W.S.F. Schuster, Auteur ; D.R. Sandquist, Auteur ; S.L. Philips, Auteur ; J.R. Ehleringer, Auteur . - 1992 . - pp. 332-337 : graph., réf. Extrait d'Oecologia - Vol.91 - n°3 Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Communauté végétale ; Désert ; Isotope ; Carbone ; Phytoécologie ; Potentiel hydrique ; Relation plante eau Résumé : Carbon isotope discrimination (Delta) was compared between populations of dominant perennial plant species, differing in life expectancy, in two deserts with contrasting vegetation types. In both deserts, plants of the shorter-lived species showed significantly higher Delta and greater intrapopulation variance in this character compared to the long-lived species. These results indicate underlying differences in gas-exchange physiology, and suggest a positive correlation between water-use efficiency and lifespan in desert plants. Differences in variance for this character may reflect greater microenvironmental variation experienced by shorter-lived plants and/or different forms of selection acting on water-use traits. Spatial distributions were significantly clustered for the shorter-lived species and significantly uniform for the long-lived species, indicating that competition has been important in the development of the long-lived populations. The long-lived Larrea tridentata showed a significant, negative correlation between Delta and Thiessen polygon area, suggesting a positive relationship between water-use efficiency and longevity within this species. This relationship was weakly supported in the other warm desert species, Encelia farinosa, but was not observed within populations of the cold desert species, Gutierrezia microcephala and Coleogyne ramosissima. These results suggest that Delta reflects key aspects of plant metabolism related to lifespan; these differences may ultimately influence interactions among desert plants and the structure of desert plant communities. Type de document : Tiré à part Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=146982

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Stable isotopes in ecological research... Workshop held at the University of California, april 1986. / P.W. Rundel (1988)

Public ISBD Titre : Stable isotopes in ecological research... Workshop held at the University of California, april 1986. Type de document : texte imprimé Auteurs : P.W. Rundel, Editeur scientifique ; J.R. Ehleringer, Editeur scientifique ; K.A. Nagy, Editeur scientifique Editeur : Tokyo : Springer Année de publication : 1988 Collection : Ecological Studies num. 68 Importance : XV-525 p. ; 24 cm Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Écologie ; Isotope ; Bilan hydrique ; Cerne ; Méthane ; Pollution atmosphérique ; Soufre Liste Plan de classement 120 (Ecologie générale. Généralités sur les écosystèmes) [Classement GFDC] Autres descripteurs METHODE ETUDE ; ECOPHYSIOLOGIE ; BILAN AZOTE ; BILAN CARBONE Type de document : Livre Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=80601 Stable isotopes in ecological research... Workshop held at the University of California, april 1986. [texte imprimé] / P.W. Rundel, Editeur scientifique ; J.R. Ehleringer, Editeur scientifique ; K.A. Nagy, Editeur scientifique . - Tokyo : Springer, 1988 . - XV-525 p. ; 24 cm. - (Ecological Studies; 68) . Langues : Anglais (eng) Catégories : Thésaurus Agrovoc Écologie ; Isotope ; Bilan hydrique ; Cerne ; Méthane ; Pollution atmosphérique ; Soufre Liste Plan de classement 120 (Ecologie générale. Généralités sur les écosystèmes) [Classement GFDC] Autres descripteurs METHODE ETUDE ; ECOPHYSIOLOGIE ; BILAN AZOTE ; BILAN CARBONE Type de document : Livre Permalien de la notice : https://infodoc.agroparistech.fr/index.php?lvl=notice_display&id=80601

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