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Modelling metabolic CO 2 evolution – a fresh perspective on respiration
Author(s) -
SWEETLOVE LEE J.,
WILLIAMS THOMAS C. R.,
CHEUNG C. Y. MAURICE,
RATCLIFFE R. GEORGE
Publication year - 2013
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/pce.12105
Subject(s) - respiration , pentose phosphate pathway , flux (metallurgy) , metabolic flux analysis , metabolic pathway , oxidative phosphorylation , cellular respiration , biology , metabolism , chemistry , biochemistry , botany , glycolysis , organic chemistry
Abstract Respiration is a major contributor to net exchange of CO 2 between plants and the atmosphere and thus an important aspect of the vegetation component of global climate change models. However, a mechanistic model of respiration is lacking, and so here we explore the potential for flux balance analysis ( FBA ) to predict cellular CO 2 evolution rates. Metabolic flux analysis reveals that respiration is not always the dominant source of CO 2 , and that metabolic processes such as the oxidative pentose phosphate pathway ( OPPP ) and lipid synthesis can be quantitatively important. Moreover, there is considerable variation in the metabolic origin of evolved CO 2 between tissues, species and conditions. Comparison of FBA ‐predicted CO 2 evolution profiles with those determined from flux measurements reveals that FBA is able to predict the metabolic origin of evolved CO 2 in different tissues/species and under different conditions. However, FBA is poor at predicting flux through certain metabolic processes such as the OPPP and we identify the way in which maintenance costs are accounted for as a major area of improvement for future FBA studies. We conclude that FBA , in its standard form, can be used to predict CO 2 evolution in a range of plant tissues and in response to environment.