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Thermal acclimation of leaf photosynthetic traits in an evergreen woodland, consistent with the coordination hypothesis
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bg-15-3461-2018.pdf | Published version | 1.22 MB | Adobe PDF | View/Open |
Title: | Thermal acclimation of leaf photosynthetic traits in an evergreen woodland, consistent with the coordination hypothesis |
Authors: | Togashi, HF Prentice, IC Atkin, OK Macfarlane, C Prober, SM Bloomfield, KJ Evans, BJ |
Item Type: | Journal Article |
Abstract: | Ecosystem models commonly assume that key photosynthetic traits, such as carboxylation capacity measured at a standard temperature, are constant in time. The temperature responses of modelled photosynthetic or respiratory rates then depend entirely on enzyme kinetics. Optimality considerations, however, suggest this assumption may be incorrect. The "coordination hypothesis" (that Rubisco- and electron-transport-limited rates of photosynthesis are co-limiting under typical daytime conditions) predicts, instead, that carboxylation (Vcmax) capacity should acclimate so that it increases somewhat with growth temperature but less steeply than its instantaneous response, implying that Vcmax when normalized to a standard temperature (e.g. 25 °C) should decline with growth temperature. With additional assumptions, similar predictions can be made for electron-transport capacity (Jmax) and mitochondrial respiration in the dark (Rdark). To explore these hypotheses, photosynthetic measurements were carried out on woody species during the warm and the cool seasons in the semi-arid Great Western Woodlands, Australia, under broadly similar light environments. A consistent proportionality between Vcmax and Jmax was found across species. Vcmax, Jmax and Rdark increased with temperature in most species, but their values standardized to 25 °C declined. The ci : ca ratio increased slightly with temperature. The leaf N : P ratio was lower in the warm season. The slopes of the relationships between log-transformed Vcmax and Jmax and temperature were close to values predicted by the coordination hypothesis but shallower than those predicted by enzyme kinetics. |
Issue Date: | 11-Jun-2018 |
Date of Acceptance: | 22-May-2018 |
URI: | http://hdl.handle.net/10044/1/61089 |
DOI: | https://dx.doi.org/10.5194/bg-15-3461-2018 |
ISSN: | 1726-4170 |
Publisher: | Copernicus Publications |
Start Page: | 3461 |
End Page: | 3474 |
Journal / Book Title: | Biogeosciences |
Volume: | 15 |
Issue: | 11 |
Copyright Statement: | © 2018 The Author(s). This work is distributed under the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/). |
Sponsor/Funder: | AXA Research Fund |
Funder's Grant Number: | AXA Chair Programme in Biosphere and Climate Impacts |
Keywords: | Science & Technology Life Sciences & Biomedicine Physical Sciences Ecology Geosciences, Multidisciplinary Environmental Sciences & Ecology Geology TEMPERATURE RESPONSE FUNCTIONS BIOCHEMICALLY BASED MODEL LIMITED PHOTOSYNTHESIS DECIDUOUS FOREST RESPIRATION NITROGEN LEAVES C-3 PARAMETERS CO2 04 Earth Sciences 05 Environmental Sciences 06 Biological Sciences Meteorology & Atmospheric Sciences |
Publication Status: | Published |
Open Access location: | https://www.biogeosciences.net/15/3461/2018/ |
Online Publication Date: | 2018-06-11 |
Appears in Collections: | Department of Life Sciences |