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Media type:
E-Article
Title:
Laisk measurements in the nonsteady state: Tests in plants exposed to warming and variable CO2 concentrations
Contributor:
Schmiege, Stephanie C;
Sharkey, Thomas D;
Walker, Berkley;
Hammer, Julia;
Way, Danielle A
imprint:
Oxford University Press (OUP), 2023
Published in:Plant Physiology
Language:
English
DOI:
10.1093/plphys/kiad305
ISSN:
0032-0889;
1532-2548
Origination:
Footnote:
Description:
<jats:title>Abstract</jats:title>
<jats:p>Light respiration (RL) is an important component of plant carbon balance and a key parameter in photosynthesis models. RL is often measured using the Laisk method, a gas exchange technique that is traditionally employed under steady-state conditions. However, a nonsteady-state dynamic assimilation technique (DAT) may allow for more rapid Laisk measurements. In 2 studies, we examined the efficacy of DAT for estimating RL and the parameter Ci* (the intercellular CO2 concentration where Rubisco's oxygenation velocity is twice its carboxylation velocity), which is also derived from the Laisk technique. In the first study, we compared DAT and steady-state RL and Ci* estimates in paper birch (Betula papyrifera) growing under control and elevated temperature and CO2 concentrations. In the second, we compared DAT-estimated RL and Ci* in hybrid poplar (Populus nigra L. × P. maximowiczii A. Henry “NM6”) exposed to high or low CO2 concentration pre-treatments. The DAT and steady-state methods provided similar RL estimates in B. papyrifera, and we found little acclimation of RL to temperature or CO2; however, Ci* was higher when measured with DAT compared to steady-state methods. These Ci* differences were amplified by the high or low CO2 pre-treatments. We propose that changes in the export of glycine from photorespiration may explain these apparent differences in Ci*.</jats:p>