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Carbon isotopic composition and oxygen isotopic enrichment in phloem and total leaf organic matter of European beech ( Fagus sylvatica L.) along a climate gradient
Author(s) -
KEITEL CLAUDIA,
MATZARAKIS ANDREAS,
RENNENBERG HEINZ,
GESSLER ARTHUR
Publication year - 2006
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.1365-3040.2006.01520.x
Subject(s) - beech , fagus sylvatica , stomatal conductance , environmental science , vapour pressure deficit , transect , chemistry , botany , transpiration , photosynthesis , atmospheric sciences , ecology , biology , geology
This study investigated the influence of climate on the carbon isotopic composition ( δ 13 C) and oxygen isotopic enrichment ( Δ 18 O) above the source water of different organic matter pools in European beech. In July and September 2002, δ 13 C and Δ 18 O were determined in phloem carbohydrates and in bulk foliage of adult beech trees along a transect from central Germany to southern France, where beech reaches its southernmost distributional limit. The data were related to meteorological and physiological parameters. The climate along the transect stretches from temperate [subcontinental (SC)] to submediterranean (SM). Both δ 13 C leaf and Δ 18 O leaf were representative of site‐specific long‐term environmental conditions. δ 13 C of leaves collected in September was indicative of stomatal conductance, vapour pressure deficit (VPD) and radiation availability of the current growing season. Δ 18 O was mainly correlated to mean growing season relative humidity (RH) and VPD. In contrast to the leaves, δ 13 C phloem varied considerably between July and September and was well correlated with canopy stomatal conductance ( G s ) in a 2 d integral prior to phloem sampling. The relationship between δ 13 C and Δ 18 O in both leaves and phloem sap points, however, to a combined influence of stomatal conductance and photosynthetic capacity on the variation of δ 13 C along the transect. Δ 18 O phloem could be described by applying a model that included 18 O fractionation associated with water exchange between the leaf and the atmosphere and with the production of organic matter. Hence, isotope signatures can be used as effective tools to assess the water balance of beech, and thus, help predict the effects of climatic change on one of the ecologically and economically most important tree species in Central Europe.