• Medientyp: E-Artikel
  • Titel: Laisk measurements in the nonsteady state: Tests in plants exposed to warming and variable CO2 concentrations
  • Beteiligte: Schmiege, Stephanie C; Sharkey, Thomas D; Walker, Berkley; Hammer, Julia; Way, Danielle A
  • Erschienen: Oxford University Press (OUP), 2023
  • Erschienen in: Plant Physiology, 193 (2023) 2, Seite 1045-1057
  • Sprache: Englisch
  • DOI: 10.1093/plphys/kiad305
  • ISSN: 1532-2548; 0032-0889
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  • Beschreibung: Abstract 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*.