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Carboxylation Capacity Can Limit C(3) Photosynthesis at Elevated CO(2) throughout Diurnal Cycles

The response of carbon fixation in C(3) plants to elevated CO(2) is relatively larger when photosynthesis is limited by carboxylation capacity (V(C)) than when limited by electron transport (J). Recent experiments under controlled, steady-state conditions have shown that photosynthesis at elevated C...

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Autor principal: Bunce, James
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8706162/
https://www.ncbi.nlm.nih.gov/pubmed/34961074
http://dx.doi.org/10.3390/plants10122603
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author Bunce, James
author_facet Bunce, James
author_sort Bunce, James
collection PubMed
description The response of carbon fixation in C(3) plants to elevated CO(2) is relatively larger when photosynthesis is limited by carboxylation capacity (V(C)) than when limited by electron transport (J). Recent experiments under controlled, steady-state conditions have shown that photosynthesis at elevated CO(2) may be limited by V(C) even at limiting PPFD. These experiments were designed to test whether this also occurs in dynamic field environments. Leaf gas exchange was recorded every 5 min using two identical instruments both attached to the same leaf. The CO(2) concentration in one instrument was controlled at 400 μmol mol(−1) and one at 600 μmol mol(−1). Leaves were exposed to ambient sunlight outdoors, and cuvette air temperatures tracked ambient outside air temperature. The water content of air in the leaf cuvettes was kept close to that of the ambient air. These measurements were conducted on multiple, mostly clear days for each of three species, Glycine max, Lablab purpureus, and Hemerocallis fulva. The results indicated that in all species, photosynthesis was limited by V(C) rather than J at both ambient and elevated CO(2) both at high midday PPFDs and also at limiting PPFDs in the early morning and late afternoon. During brief reductions in PPFD due to midday clouds, photosynthesis became limited by J. The net result of the apparent deactivation of Rubisco at low PPFD was that the relative stimulation of diurnal carbon fixation at elevated CO(2) was larger than would be predicted when assuming limitation of photosynthesis by J at low PPFD.
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spelling pubmed-87061622021-12-25 Carboxylation Capacity Can Limit C(3) Photosynthesis at Elevated CO(2) throughout Diurnal Cycles Bunce, James Plants (Basel) Communication The response of carbon fixation in C(3) plants to elevated CO(2) is relatively larger when photosynthesis is limited by carboxylation capacity (V(C)) than when limited by electron transport (J). Recent experiments under controlled, steady-state conditions have shown that photosynthesis at elevated CO(2) may be limited by V(C) even at limiting PPFD. These experiments were designed to test whether this also occurs in dynamic field environments. Leaf gas exchange was recorded every 5 min using two identical instruments both attached to the same leaf. The CO(2) concentration in one instrument was controlled at 400 μmol mol(−1) and one at 600 μmol mol(−1). Leaves were exposed to ambient sunlight outdoors, and cuvette air temperatures tracked ambient outside air temperature. The water content of air in the leaf cuvettes was kept close to that of the ambient air. These measurements were conducted on multiple, mostly clear days for each of three species, Glycine max, Lablab purpureus, and Hemerocallis fulva. The results indicated that in all species, photosynthesis was limited by V(C) rather than J at both ambient and elevated CO(2) both at high midday PPFDs and also at limiting PPFDs in the early morning and late afternoon. During brief reductions in PPFD due to midday clouds, photosynthesis became limited by J. The net result of the apparent deactivation of Rubisco at low PPFD was that the relative stimulation of diurnal carbon fixation at elevated CO(2) was larger than would be predicted when assuming limitation of photosynthesis by J at low PPFD. MDPI 2021-11-27 /pmc/articles/PMC8706162/ /pubmed/34961074 http://dx.doi.org/10.3390/plants10122603 Text en © 2021 by the author. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Communication
Bunce, James
Carboxylation Capacity Can Limit C(3) Photosynthesis at Elevated CO(2) throughout Diurnal Cycles
title Carboxylation Capacity Can Limit C(3) Photosynthesis at Elevated CO(2) throughout Diurnal Cycles
title_full Carboxylation Capacity Can Limit C(3) Photosynthesis at Elevated CO(2) throughout Diurnal Cycles
title_fullStr Carboxylation Capacity Can Limit C(3) Photosynthesis at Elevated CO(2) throughout Diurnal Cycles
title_full_unstemmed Carboxylation Capacity Can Limit C(3) Photosynthesis at Elevated CO(2) throughout Diurnal Cycles
title_short Carboxylation Capacity Can Limit C(3) Photosynthesis at Elevated CO(2) throughout Diurnal Cycles
title_sort carboxylation capacity can limit c(3) photosynthesis at elevated co(2) throughout diurnal cycles
topic Communication
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8706162/
https://www.ncbi.nlm.nih.gov/pubmed/34961074
http://dx.doi.org/10.3390/plants10122603
work_keys_str_mv AT buncejames carboxylationcapacitycanlimitc3photosynthesisatelevatedco2throughoutdiurnalcycles