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Limitation of net CO 2 assimilation rate by internal resistances to CO 2 transfer in the leaves of two tree species ( Fagus sylvatica L. and Castanea sativa Mill.)
Author(s) -
EPRON D.,
GODARD D.,
CORNIC G.,
GENTY B.
Publication year - 1995
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1995.tb00542.x
Subject(s) - fagus sylvatica , chemistry , photosynthesis , botany , rubisco , analytical chemistry (journal) , conductance , carboxylation , beech , biology , catalysis , chromatography , physics , biochemistry , condensed matter physics
Using a combination of gas‐exchange and chlorophyll fluorescence measurements, low apparent CO 2 /O 2 specificity factors (1300 mol mol −1 ) were estimated for the leaves of two deciduous tree species (Fagus sylvatica and Castanea sativa). These low values contrasted with those estimated for two herbaceous species and were ascribed to a drop in the CO 2 mole fraction between the intercellular airspace (C i ) and the catalytic site of Rubisco (C c ) due to internal resistances to CO 2 transfer. C c . was calculated assuming a specificity of Rubisco value of 2560 mol mol −1 . The drop between C i and C c was used to calculate the internal conductance for CO 2 (g i ). A good correlation between mean values of net CO 2 assimilation rate (A) and g i was observed within a set of data obtained using 13 woody plant species, including our own data. We report that the relative limitation of A, which can be ascribed to internal resistances to CO 2 transfer, was 24–30%. High internal resistances to CO 2 transfer may explain the low apparent maximal rates of carboxylation and electron transport of some woody plant species calculated from A/C i curves.