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Does the 13 C of foliage‐respired CO 2 and biochemical pools reflect the 13 C of recently assimilated carbon?
Author(s) -
MORTAZAVI BEHZAD,
CONTE MAUREEN H.,
CHANTON JEFFREY P.,
SMITH MATTHEW C.,
WEBER J. C.,
CRUMSEY JASMINE,
GHASHGHAIE JALEH
Publication year - 2009
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.1365-3040.2009.01999.x
Subject(s) - carbon 14 , carbon fibers , chemistry , radiochemistry , isotopes of carbon , environmental chemistry , physics , materials science , total organic carbon , nuclear physics , composite number , composite material
Isotopic labelling experiments were conducted to assess relationships among 13 C of recently assimilated carbon ( δC A ), foliage respiration ( δC F ), soluble carbohydrate ( δC SC ), leaf waxes ( δC LW ) and bulk organic matter ( δC OM ). Slash pine, sweetgum and maize were grown under 13 C depleted CO 2 to label biomass and then placed under ambient conditions to monitor the loss of label. In pine and sweetgum, δC F of labelled plants (∼−44 and −35‰, respectively) rapidly approached control values but remained depleted by ∼4–6‰ after 3–4 months. For these tree species, no or minimal label was lost from δC SC , δC LW and δC OM during the observation periods. δC F and δC SC of labelled maize plants rapidly changed and were indistinguishable from controls after 1 month, while δC LW and δC OM more slowly approached control values and remained depleted by 2–6‰. Changes in δC F in slash pine and sweetgum fit a two‐pool exponential model, with the fast turnover metabolic pool (∼3–4 d half‐life) constituting only 1–2% of the total. In maize, change in δC F fits a single pool model with a half‐life of 6.4 d. The 13 C of foliage respiration and biochemical pools reflect temporally integrated values of δC A , with change in isotopic composition dampened by the size of metabolic carbon reserves and turnover rates.