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Summary Leaf dark respiration (Rdark), an important yet rarely quantified component of carbon cycling in forest ecosystems, is often simulated from leaf traits such as the maximum carboxylation capacity (Vcmax), leaf mass per area (LMA), nitrogen (N) and phosphorus (P) concentrations, in terrestrial biosphere models. However, the validity of these relationships across forest types remains to be thoroughly assessed.Here, we analyzedRdarkvariability and its associations withVcmaxand other leaf traits across three temperate, subtropical and tropical forests in China, evaluating the effectiveness of leaf spectroscopy as a superior monitoring alternative.We found that leaf magnesium and calcium concentrations were more significant in explaining cross‐siteRdarkthan commonly used traits like LMA, N and P concentrations, but univariate trait–Rdarkrelationships were always weak (r2 ≤ 0.15) and forest‐specific. Although multivariate relationships of leaf traits improved the model performance, leaf spectroscopy outperformed trait–Rdarkrelationships, accurately predicted cross‐siteRdark(r2 = 0.65) and pinpointed the factors contributing toRdarkvariability.Our findings reveal a few novel traits with greater cross‐site scalability regardingRdark, challenging the use of empirical trait–Rdarkrelationships in process models and emphasize the potential of leaf spectroscopy as a promising alternative for estimatingRdark, which could ultimately improve process modeling of terrestrial plant respiration.
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Reduced global plant respiration due to the acclimation of leaf dark respiration coupled with photosynthesis
Summary Leaf dark respiration (Rd) acclimates to environmental changes. However, the magnitude, controls and time scales of acclimation remain unclear and are inconsistently treated in ecosystem models.We hypothesized thatRdand Rubisco carboxylation capacity (Vcmax) at 25°C (Rd,25,Vcmax,25) are coordinated so thatRd,25variations supportVcmax,25at a level allowing full light use, withVcmax,25reflecting daytime conditions (for photosynthesis), andRd,25/Vcmax,25reflecting night‐time conditions (for starch degradation and sucrose export). We tested this hypothesis temporally using a 5‐yr warming experiment, and spatially using an extensive field‐measurement data set. We compared the results to three published alternatives:Rd,25declines linearly with daily average prior temperature;Rdat average prior night temperatures tends towards a constant value; andRd,25/Vcmax,25is constant.Our hypothesis accounted for more variation in observedRd,25over time (R2 = 0.74) and space (R2 = 0.68) than the alternatives. Night‐time temperature dominated the seasonal time‐course ofRd, with an apparent response time scale ofc.2 wk.Vcmaxdominated the spatial patterns.Our acclimation hypothesis results in a smaller increase in globalRdin response to rising CO2and warming than is projected by the two of three alternative hypotheses, and by current models.
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- PAR ID:
- 10483433
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 241
- Issue:
- 2
- ISSN:
- 0028-646X
- Format(s):
- Medium: X Size: p. 578-591
- Size(s):
- p. 578-591
- Sponsoring Org:
- National Science Foundation
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