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On the 13 C/ 12 C isotopic signal of day and night respiration at the mesocosm level
Author(s) -
TCHERKEZ GUILLAUME,
SCHÄUFELE RUDI,
NOGUÉS SALVADOR,
PIEL CLÉMENT,
BOOM ARNOUD,
LANIGAN GARY,
BARBAROUX CÉCILE,
MATA CATARINA,
ELHANI SLIMAN,
HEMMING DEBBIE,
MAGUAS CHRISTINA,
YAKIR DAN,
BADECK FRANZ W.,
GRIFFITHS HOWARD,
SCHNYDER HANS,
GHASHGHAIE JALEH
Publication year - 2010
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.1365-3040.2010.02115.x
Subject(s) - mesocosm , photorespiration , respiration , darkness , isotopes of carbon , photosynthesis , zoology , fractionation , chemistry , botany , biology , environmental chemistry , ecosystem , ecology , total organic carbon , chromatography
While there is currently intense effort to examine the 13 C signal of CO 2 evolved in the dark, less is known on the isotope composition of day‐respired CO 2 . This lack of knowledge stems from technical difficulties to measure the pure respiratory isotopic signal: day respiration is mixed up with photorespiration, and there is no obvious way to separate photosynthetic fractionation (pure c i / c a effect) from respiratory effect (production of CO 2 with a different δ 13 C value from that of net‐fixed CO 2 ) at the ecosystem level. Here, we took advantage of new simple equations, and applied them to sunflower canopies grown under low and high [CO 2 ]. We show that whole mesocosm‐respired CO 2 is slightly 13 C depleted in the light at the mesocosm level (by 0.2–0.8‰), while it is slightly 13 C enriched in darkness (by 1.5–3.2‰). The turnover of the respiratory carbon pool after labelling appears similar in the light and in the dark, and accordingly, a hierarchical clustering analysis shows a close correlation between the 13 C abundance in day‐ and night‐evolved CO 2 . We conclude that the carbon source for respiration is similar in the dark and in the light, but the metabolic pathways associated with CO 2 production may change, thereby explaining the different 12 C/ 13 C respiratory fractionations in the light and in the dark.