%0 Journal Article %1 citeulike:12460455 %A Rogers, A. %A Allen, D. J. %A Davey, P. A. %A Morgan, P. B. %A Ainsworth, E. A. %A Bernacchi, C. J. %A Cornic, G. %A Dermody, O. %A Dohleman, F. G. %A Heaton, E. A. %A Mahoney, J. %A Zhu, %A Delucia, E. H. %A Ort, D. R. %A Long, S. P. %D 2004 %I Blackwell Science Ltd %J Plant, Cell & Environment %K citeulikeExport co2, crop, face, face\_nutrients, gas\_exchange, p1, photosynthesis, soy, soyface, techniques %N 4 %P 449--458 %R 10.1111/j.1365-3040.2004.01163.x %T Leaf photosynthesis and carbohydrate dynamics of soybeans grown throughout their life-cycle under Free-Air Carbon dioxide Enrichment %U http://dx.doi.org/10.1111/j.1365-3040.2004.01163.x %V 27 %X A lower than theoretically expected increase in leaf photosynthesis with long-term elevation of carbon dioxide concentration (CO2) is often attributed to limitations in the capacity of the plant to utilize the additional photosynthate, possibly resulting from restrictions in rooting volume, nitrogen supply or genetic constraints. Field-grown, nitrogen-fixing soybean with indeterminate flowering might therefore be expected to escape these limitations. Soybean was grown from emergence to grain maturity in ambient air (372 µmol mol−1CO2) and in air enriched with CO2 (552 µmol mol−1CO2) using Free-Air CO2 Enrichment (FACE) technology. The diurnal courses of leaf CO2 uptake (A) and stomatal conductance (gs) for upper canopy leaves were followed throughout development from the appearance of the first true leaf to the completion of seed filling. Across the growing season the daily integrals of leaf photosynthetic CO2 uptake (A′) increased by 24.6\% in elevated CO2 and the average mid-day gs decreased by 21.9\%. The increase in A′ was about half the 44.5\% theoretical maximum increase calculated from Rubisco kinetics. There was no evidence that the stimulation of A was affected by time of day, as expected if elevated CO2 led to a large accumulation of leaf carbohydrates towards the end of the photoperiod. In general, the proportion of assimilated carbon that accumulated in the leaf as non-structural carbohydrate over the photoperiod was small (< 10\%) and independent of CO2 treatment. By contrast to A′, daily integrals of PSII electron transport measured by modulated chlorophyll fluorescence were not significantly increased by elevated CO2. This indicates that A at elevated CO2 in these field conditions was predominantly ribulose-1,5-bisphosphate (RubP) limited rather than Rubisco limited. There was no evidence of any loss of stimulation toward the end of the growing season; the largest stimulation of A′ occurred during late seed filling. The stimulation of photosynthesis was, however, transiently lost for a brief period just before seed fill. At this point, daytime accumulation of foliar carbohydrates was maximal, and the hexose:sucrose ratio in plants grown at elevated CO2 was significantly larger than that in plants grown at current CO2. The results show that even for a crop lacking the constraints that have been considered to limit the responses of C3 plants to rising CO2 in the long term, the actual increase in A over the growing season is considerably less than the increase predicted from theory.

@article{citeulike:12460455, abstract = {{A lower than theoretically expected increase in leaf photosynthesis with long-term elevation of carbon dioxide concentration ([CO2]) is often attributed to limitations in the capacity of the plant to utilize the additional photosynthate, possibly resulting from restrictions in rooting volume, nitrogen supply or genetic constraints. Field-grown, nitrogen-fixing soybean with indeterminate flowering might therefore be expected to escape these limitations. Soybean was grown from emergence to grain maturity in ambient air (372 µmol mol−1[CO2]) and in air enriched with CO2 (552 µmol mol−1[CO2]) using Free-Air CO2 Enrichment (FACE) technology. The diurnal courses of leaf CO2 uptake (A) and stomatal conductance (gs) for upper canopy leaves were followed throughout development from the appearance of the first true leaf to the completion of seed filling. Across the growing season the daily integrals of leaf photosynthetic CO2 uptake (A′) increased by 24.6\% in elevated [CO2] and the average mid-day gs decreased by 21.9\%. The increase in A′ was about half the 44.5\% theoretical maximum increase calculated from Rubisco kinetics. There was no evidence that the stimulation of A was affected by time of day, as expected if elevated [CO2] led to a large accumulation of leaf carbohydrates towards the end of the photoperiod. In general, the proportion of assimilated carbon that accumulated in the leaf as non-structural carbohydrate over the photoperiod was small (< 10\%) and independent of [CO2] treatment. By contrast to A′, daily integrals of PSII electron transport measured by modulated chlorophyll fluorescence were not significantly increased by elevated [CO2]. This indicates that A at elevated [CO2] in these field conditions was predominantly ribulose-1,5-bisphosphate (RubP) limited rather than Rubisco limited. There was no evidence of any loss of stimulation toward the end of the growing season; the largest stimulation of A′ occurred during late seed filling. The stimulation of photosynthesis was, however, transiently lost for a brief period just before seed fill. At this point, daytime accumulation of foliar carbohydrates was maximal, and the hexose:sucrose ratio in plants grown at elevated [CO2] was significantly larger than that in plants grown at current [CO2]. The results show that even for a crop lacking the constraints that have been considered to limit the responses of C3 plants to rising [CO2] in the long term, the actual increase in A over the growing season is considerably less than the increase predicted from theory.}}, added-at = {2019-03-31T01:14:40.000+0100}, author = {Rogers, A. and Allen, D. J. and Davey, P. A. and Morgan, P. B. and Ainsworth, E. A. and Bernacchi, C. J. and Cornic, G. and Dermody, O. and Dohleman, F. G. and Heaton, E. A. and Mahoney, J. and Zhu and Delucia, E. H. and Ort, D. R. and Long, S. P.}, biburl = {https://www.bibsonomy.org/bibtex/2892cc1d4f3ea11f68c4c1927dd5953c1/dianella}, citeulike-article-id = {12460455}, citeulike-linkout-0 = {http://dx.doi.org/10.1111/j.1365-3040.2004.01163.x}, comment = {(private-note)A, A', gs, non structural carbohydrates, hexose sucrose in leaf soil type 2001 planting}, day = 1, doi = {10.1111/j.1365-3040.2004.01163.x}, interhash = {4ccea2f5184424d85ecb19ac471e3daf}, intrahash = {892cc1d4f3ea11f68c4c1927dd5953c1}, journal = {Plant, Cell \& Environment}, keywords = {citeulikeExport co2, crop, face, face\_nutrients, gas\_exchange, p1, photosynthesis, soy, soyface, techniques}, month = apr, number = 4, pages = {449--458}, posted-at = {2013-07-05 06:03:03}, priority = {5}, publisher = {Blackwell Science Ltd}, timestamp = {2019-03-31T01:16:26.000+0100}, title = {{Leaf photosynthesis and carbohydrate dynamics of soybeans grown throughout their life-cycle under Free-Air Carbon dioxide Enrichment}}, url = {http://dx.doi.org/10.1111/j.1365-3040.2004.01163.x}, volume = 27, year = 2004 }