Reduced global plant respiration due to the acclimation of leaf dark respiration coupled with photosynthesis

• Published in: The New phytologist Vol. 241; no. 2
• Main Authors: Ren, Yanghang, Wang, Han, Harrison, Sandy P., Prentice, I. Colin, Atkin, Owen K., Smith, Nicholas G., Mengoli, Giulia, Stefanski, Artur, Reich, Peter B.
• Format: Journal Article
• Language: English
• Published: United Kingdom Wiley-Blackwell 28.10.2023
• ISSN: 0028-646X; 1469-8137

Summary <list list-type='bullet'> Leaf dark respiration ( R d ) acclimates to environmental changes. However, the magnitude, controls and time scales of acclimation remain unclear and are inconsistently treated in ecosystem models. We hypothesized that R d and Rubisco carboxylation capacity ( V cmax ) at 25°C ( R d,25 , V cmax,25 ) are coordinated so that R d,25 variations support V cmax,25 at a level allowing full light use, with V cmax,25 reflecting daytime conditions (for photosynthesis), and R d,25 / V cmax,25 reflecting 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: R d,25 declines linearly with daily average prior temperature; R d at average prior night temperatures tends towards a constant value; and R d,25 / V cmax,25 is constant. Our hypothesis accounted for more variation in observed R d,25 over time ( R 2  = 0.74) and space ( R 2  = 0.68) than the alternatives. Night‐time temperature dominated the seasonal time‐course of R d , with an apparent response time scale of c. 2 wk. V cmax dominated the spatial patterns. Our acclimation hypothesis results in a smaller increase in global R d in response to rising CO 2 and warming than is projected by the two of three alternative hypotheses, and by current models.