Down-regulation of light-saturated photosynthesis (A
sat) at elevated atmospheric CO2 concentration, CO2, has been demonstrated for many C3 species and is often associated with inability to utilize additional photosynthate and/or nitrogen limitation. In soybean, a nitrogen-fixing species, both limitations are less likely than in crops lacking an N-fixing symbiont. Prior studies have used controlled environment or field enclosures where the artificial environment can modify responses to CO2. A soybean free air CO2 enrichment (FACE) facility has provided the first opportunity to analyze the effects of elevated CO2 on photosynthesis under fully open-air conditions. Potential ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylation (V
c,max) and electron transport through photosystem II (J
max) were determined from the responses of A
sat to intercellular CO2 (C
i) throughout two growing seasons. Mesophyll conductance to CO2 (g
m) was determined from the responses of A
sat and whole chain electron transport (J) to light. Elevated CO2 increased A
sat by 15–20\% even though there was a small, statistically significant, decrease in V
c,max. This differs from previous studies in that V
c,max/J
max decreased, inferring a shift in resource investment away from Rubisco. This raised the C
i at which the transition from Rubisco-limited to ribulose-1,5-bisphosphate regeneration-limited photosynthesis occurred. The decrease in V
c,max was not the result of a change in g
m, which was unchanged by elevated CO2. This first analysis of limitations to soybean photosynthesis under fully open-air conditions reveals important differences to prior studies that have used enclosures to elevate CO2, most significantly a smaller response of A
sat and an apparent shift in resources away from Rubisco relative to capacity for electron transport.
%0 Journal Article
%1 citeulike:12889538
%A Bernacchi, Carl J.
%A Morgan, Patrick B.
%A Ort, Donald R.
%A Long, Stephen P.
%B Planta
%D 2005
%I Springer-Verlag
%J Planta
%K acclimation, citeulikeExport face, face\_nutrients, gas\_exchange, photosynthesis, rubisco, soy, soyface
%N 3
%P 434--446
%R 10.1007/s00425-004-1320-8
%T The growth of soybean under free air CO2 enrichment (FACE) stimulates photosynthesis while decreasing in vivo Rubisco capacity
%U http://dx.doi.org/10.1007/s00425-004-1320-8
%V 220
%X Down-regulation of light-saturated photosynthesis (A
sat) at elevated atmospheric CO2 concentration, CO2, has been demonstrated for many C3 species and is often associated with inability to utilize additional photosynthate and/or nitrogen limitation. In soybean, a nitrogen-fixing species, both limitations are less likely than in crops lacking an N-fixing symbiont. Prior studies have used controlled environment or field enclosures where the artificial environment can modify responses to CO2. A soybean free air CO2 enrichment (FACE) facility has provided the first opportunity to analyze the effects of elevated CO2 on photosynthesis under fully open-air conditions. Potential ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylation (V
c,max) and electron transport through photosystem II (J
max) were determined from the responses of A
sat to intercellular CO2 (C
i) throughout two growing seasons. Mesophyll conductance to CO2 (g
m) was determined from the responses of A
sat and whole chain electron transport (J) to light. Elevated CO2 increased A
sat by 15–20\% even though there was a small, statistically significant, decrease in V
c,max. This differs from previous studies in that V
c,max/J
max decreased, inferring a shift in resource investment away from Rubisco. This raised the C
i at which the transition from Rubisco-limited to ribulose-1,5-bisphosphate regeneration-limited photosynthesis occurred. The decrease in V
c,max was not the result of a change in g
m, which was unchanged by elevated CO2. This first analysis of limitations to soybean photosynthesis under fully open-air conditions reveals important differences to prior studies that have used enclosures to elevate CO2, most significantly a smaller response of A
sat and an apparent shift in resources away from Rubisco relative to capacity for electron transport.
@article{citeulike:12889538,
abstract = {{Down-regulation of light-saturated photosynthesis (A
sat) at elevated atmospheric CO2 concentration, [CO2], has been demonstrated for many C3 species and is often associated with inability to utilize additional photosynthate and/or nitrogen limitation. In soybean, a nitrogen-fixing species, both limitations are less likely than in crops lacking an N-fixing symbiont. Prior studies have used controlled environment or field enclosures where the artificial environment can modify responses to [CO2]. A soybean free air [CO2] enrichment (FACE) facility has provided the first opportunity to analyze the effects of elevated [CO2] on photosynthesis under fully open-air conditions. Potential ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylation (V
c,max) and electron transport through photosystem II (J
max) were determined from the responses of A
sat to intercellular [CO2] (C
i) throughout two growing seasons. Mesophyll conductance to CO2 (g
m) was determined from the responses of A
sat and whole chain electron transport (J) to light. Elevated [CO2] increased A
sat by 15–20\% even though there was a small, statistically significant, decrease in V
c,max. This differs from previous studies in that V
c,max/J
max decreased, inferring a shift in resource investment away from Rubisco. This raised the C
i at which the transition from Rubisco-limited to ribulose-1,5-bisphosphate regeneration-limited photosynthesis occurred. The decrease in V
c,max was not the result of a change in g
m, which was unchanged by elevated [CO2]. This first analysis of limitations to soybean photosynthesis under fully open-air conditions reveals important differences to prior studies that have used enclosures to elevate [CO2], most significantly a smaller response of A
sat and an apparent shift in resources away from Rubisco relative to capacity for electron transport.}},
added-at = {2019-03-31T01:14:40.000+0100},
author = {Bernacchi, Carl J. and Morgan, Patrick B. and Ort, Donald R. and Long, Stephen P.},
biburl = {https://www.bibsonomy.org/bibtex/201b97491abdfbf286d1feaaca8911b59/dianella},
booktitle = {Planta},
citeulike-article-id = {12889538},
citeulike-linkout-0 = {http://dx.doi.org/10.1007/s00425-004-1320-8},
citeulike-linkout-1 = {http://link.springer.com/article/10.1007/s00425-004-1320-8},
doi = {10.1007/s00425-004-1320-8},
interhash = {abcfcefb86f174b2dc3828ce1cc21016},
intrahash = {01b97491abdfbf286d1feaaca8911b59},
journal = {Planta},
keywords = {acclimation, citeulikeExport face, face\_nutrients, gas\_exchange, photosynthesis, rubisco, soy, soyface},
number = 3,
pages = {434--446},
posted-at = {2014-01-03 02:59:10},
priority = {4},
publisher = {Springer-Verlag},
timestamp = {2019-03-31T01:16:26.000+0100},
title = {{The growth of soybean under free air [CO2] enrichment (FACE) stimulates photosynthesis while decreasing in vivo Rubisco capacity}},
url = {http://dx.doi.org/10.1007/s00425-004-1320-8},
volume = 220,
year = 2005
}