Premium
Short‐term dynamics of the carbon isotope composition of CO 2 emitted from a wheat agroecosystem – physiological and environmental controls
Author(s) -
Kodama N.,
Ferrio J. P.,
Brüggemann N.,
Gessler A.
Publication year - 2011
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/j.1438-8677.2010.00329.x
Subject(s) - diel vertical migration , agroecosystem , photosynthesis , biology , stable isotope ratio , respiration , environmental chemistry , fractionation , ecosystem , isotopes of carbon , carbon cycle , botany , ecology , chemistry , total organic carbon , physics , organic chemistry , quantum mechanics , agriculture
Understanding environmental and physiological controls of the variations in δ 13 C of CO 2 respired (δ 13 C R ) from different compartments of an ecosystem is important for separation of CO 2 fluxes and to assess coupling between assimilation and respiration. In a wheat field, over 3 days we characterised the temporal dynamics of δ 13 C R from shoots and roots, from the soil and from the whole agroecosystem. To evaluate the basis of potential variations in δ 13 C R , we also measured δ 13 C in different organic matter pools, as well as meteorological and gas exchange parameters. We observed strong diel variations up to ca . 6% in shoot, root and soil δ 13 C R , but not in δ 13 C of the putative organic substrates for respiration, which varied by not more than ca . 1% within 24 h. Whole ecosystem‐respired CO 2 was least depleted in 13 C in the afternoon and most negative in the early morning. We assume that temporally variable respiratory carbon isotope fractionation and changes in fluxes through metabolic pathways, rather than photosynthetic carbon isotope fractionation, governs the δ 13 C of respired CO 2 at the diel scale, and thus provides insights into the metabolic processes related to respiration under field conditions.