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The time course of acclimation to the stress of triose phosphate use limitation
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  • Alan McClain,
  • Jeffrey A. Cruz,
  • David M. Kramer,
  • Thomas Sharkey
Alan McClain
Michigan State University
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Jeffrey A. Cruz
Michigan State University
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David M. Kramer
Michigan State University
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Thomas Sharkey
Michigan State University
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Abstract

Triose-phosphate utilization (TPU) limits the maximum rate at which plants can photosynthesize. However, TPU is almost never found to be limiting photosynthesis under ambient conditions for plants. This, along with previous results showing adaptability of TPU at low temperature, suggest that TPU capacity is regulated to be just above the photosynthetic rate achievable under the prevailing conditions. A set of experiments were performed to study the adaptability of TPU capacity when plants are acclimated to elevated CO 2 concentrations. Plants held at 1500 ppm CO 2 were initially TPU limited. After 30 hours they no longer exhibited TPU limitations but they did not elevate their TPU capacity. Instead, the maximum rates of carboxylation and electron transport declined. A timecourse of regulatory responses was established. A step increase of CO 2 first caused PSI to be oxidized but after 40 s both PSI and PSII had excess electrons as a result of acceptor-side limitations. Electron flow to PSI slowed and the proton motive force increased. Eventually, non-photochemical quenching reduced electron flow sufficiently to balance the TPU limitation. Over several minutes rubisco deactivated contributing to regulation of metabolism to overcome the TPU limitation.
20 Jun 2022Submitted to Plant, Cell & Environment
20 Jun 2022Submission Checks Completed
20 Jun 2022Assigned to Editor
27 Jun 2022Reviewer(s) Assigned
01 Aug 2022Review(s) Completed, Editorial Evaluation Pending
01 Aug 2022Editorial Decision: Revise Minor
29 Aug 20221st Revision Received
30 Aug 2022Submission Checks Completed
30 Aug 2022Assigned to Editor
31 Aug 2022Reviewer(s) Assigned
14 Sep 2022Review(s) Completed, Editorial Evaluation Pending
20 Sep 2022Editorial Decision: Revise Minor
26 Sep 20222nd Revision Received