Acclimation of light and dark respiration to experimental and seasonal warming are mediated by changes in leaf nitrogen in Eucalyptus globulus
Date
2017
Authors
Crous, Kristine Y
Wallin, Goran
Atkin, Owen
Uddling, J
af Ekenstam, A
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Oxford University Press
Abstract
Quantifying the adjustments of leaf respiration in response to seasonal temperature variation and climate warming is crucial
because carbon loss from vegetation is a large but uncertain part of the global carbon cycle. We grew fast-growing Eucalyptus
globulus Labill. trees exposed to +3 °C warming and elevated CO2 in 10-m tall whole-tree chambers and measured the temperature responses of leaf mitochondrial respiration, both in light (RLight) and in darkness (RDark), over a 20–40 °C temperature range
and during two different seasons. RLight was assessed using the Laisk method. Respiration rates measured at a standard temperature (25 °C – R25) were higher in warm-grown trees and in the warm season, related to higher total leaf nitrogen (N) investment
with higher temperatures (both experimental and seasonal), indicating that leaf N concentrations modulated the respiratory capacity to changes in temperature. Once differences in leaf N were accounted for, there were no differences in R25 but the Q10 (i.e.,
short-term temperature sensitivity) was higher in late summer compared with early spring. The variation in RLight between experimental treatments and seasons was positively correlated with carboxylation capacity and photorespiration. RLight was less
responsive to short-term changes in temperature than RDark, as shown by a lower Q10 in RLight compared with RDark. The overall
light inhibition of R was ∼40%. Our results highlight the dynamic nature of leaf respiration to temperature variation and that the
responses of RLight do not simply mirror those of RDark. Therefore, it is important not to assume that RLight is the same as RDark in
ecosystem models, as doing so may lead to large errors in predicting plant CO2 release and productivity.
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Keywords
day respiration, , leaf respiration, Q10, temperature, warming., elevated CO2
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Source
Tree Physiology
Type
Journal article
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2099-12-31
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