%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Bonal, D.
%A Ponton, S.
%A Le Thiec, D.
%A Richard, B.
%A Ningre, N.
%A Herault, B.
%A Ogee, J.
%A Gonzalez, S.
%A Pignal, M.
%A Sabatier, Daniel
%A Guehl, J. M.
%T Leaf functional response to increasing atmospheric CO2 concentrations over the last century in two northern Amazonian tree species: a historical delta C-13 and delta O-18 approach using herbarium samples
%D 2011
%L fdi:010053696
%G ENG
%J Plant Cell and Environment
%@ 0140-7791
%K carbon isotope composition ; environmental change ; herbarium ; oxygen ; isotope composition ; photosynthesis ; stomata ; tropical rainforests
%M ISI:000292698900010
%N 8
%P 1332-1344
%R 10.1111/j.1365-3040.2011.02333.x
%U https://www.documentation.ird.fr/hor/fdi:010053696
%> https://www.documentation.ird.fr/intranet/publi/2011/08/010053696.pdf
%V 34
%W Horizon (IRD)
%X We assessed the extent of recent environmental changes on leaf morphological (stomatal density, stomatal surface, leaf mass per unit area) and physiological traits (carbon isotope composition, delta C-13(leaf), and discrimination, Delta C-13(leaf), oxygen isotope composition, delta O-18(leaf)) of two tropical rainforest species (Dicorynia guianensis; Humiria balsamifera) that are abundant in the Guiana shield (Northern Amazonia). Leaf samples were collected in different international herbariums to cover a 200 year time-period (1790-2004) and the whole Guiana shield. Using models describing carbon and oxygen isotope fractionations during photosynthesis, different scenarios of change in intercellular CO2 concentrations inside the leaf (C-i), stomatal conductance (g), and photosynthesis (A) were tested in order to understand leaf physiological response to increasing air CO2 concentrations (C-a). Our results confirmed that both species displayed physiological response to changing C-a. For both species, we observed a decrease of about 1.7% in delta C-13(leaf) since 1950, without significant change in Delta C-13(leaf) and leaf morphological traits. Furthermore, there was no clear change in delta O-18(leaf) for Humiria over this period. Our simulation approach revealed that an increase in A, rather than a decrease in g, explained the observed trends for these tropical rainforest species, allowing them to maintain a constant ratio of C-i/C-a.
%$ 076