TY - JOUR
T1 - Testing the "source-sink" hypothesis of down-regulation of photosynthesis in elevated [CO2] in the field with single gene substitutions in Glycine max
AU - Ainsworth, Elizabeth A.
AU - Rogers, Alistair
AU - Nelson, Randall
AU - Long, Stephen P.
N1 - Funding Information:
EAA was funded by the Graduate Research for the Environment Fellowship, Global Change Education Program, Department of Energy. SoyFACE is possible through funding by the Illinois Council for Food and Agricultural Research (CFAR), Archer Daniels Midland Company, Argonne National Laboratory, and USDA-ARS. This research was in part performed under the auspices of the US Department of Energy under contract no. DE-AC02-CH10886.
PY - 2004/3/20
Y1 - 2004/3/20
N2 - Acclimation of photosynthesis to elevated atmospheric carbon dioxide concentration was tested in lines of soybean (Glycine max) that differed by single genes that altered either the capacity to nodulate or growth habit (determinate or indeterminate growth). Both genetic changes provided, within a uniform genetic background, a test of the "source-sink" hypothesis that down-regulation of photosynthesis in elevated carbon dioxide is a result of inability to form sufficient "sinks" for the additional photosynthate. Plants were grown under ambient and elevated [CO2] (550μmol mol-1) in the field, using free air gas concentration enrichment (FACE). Mutation of the determinate cultivar, Elf, to an indeterminate form did not result in increased responsiveness to elevated [CO2]. This may reflect a large sink capacity in the selection of determinate cultivars. In elevated [CO2] only the determinate isoline of the indeterminate cultivar (Williams-dt1) and the non-nodulating genotype showed down-regulation of photosynthesis. This resulted from decreases in apparent in vivo Rubisco activity (Vc,max) and maximum rate of electron transport (Jmax). Increase in total non-structural carbohydrate (TNC) content, which is often correlated with down-regulation of photosynthesis, in Williams-dt1 was 80% greater in elevated [CO2] than in ambient [CO2] controls, compared to 40% in the indeterminate line. The results from mutations of the Williams line are consistent with the hypothesis that genetic capacity for the utilization of photosynthate is critical to the ability of plants to sustain increased photosynthesis when grown at elevated [CO2].
AB - Acclimation of photosynthesis to elevated atmospheric carbon dioxide concentration was tested in lines of soybean (Glycine max) that differed by single genes that altered either the capacity to nodulate or growth habit (determinate or indeterminate growth). Both genetic changes provided, within a uniform genetic background, a test of the "source-sink" hypothesis that down-regulation of photosynthesis in elevated carbon dioxide is a result of inability to form sufficient "sinks" for the additional photosynthate. Plants were grown under ambient and elevated [CO2] (550μmol mol-1) in the field, using free air gas concentration enrichment (FACE). Mutation of the determinate cultivar, Elf, to an indeterminate form did not result in increased responsiveness to elevated [CO2]. This may reflect a large sink capacity in the selection of determinate cultivars. In elevated [CO2] only the determinate isoline of the indeterminate cultivar (Williams-dt1) and the non-nodulating genotype showed down-regulation of photosynthesis. This resulted from decreases in apparent in vivo Rubisco activity (Vc,max) and maximum rate of electron transport (Jmax). Increase in total non-structural carbohydrate (TNC) content, which is often correlated with down-regulation of photosynthesis, in Williams-dt1 was 80% greater in elevated [CO2] than in ambient [CO2] controls, compared to 40% in the indeterminate line. The results from mutations of the Williams line are consistent with the hypothesis that genetic capacity for the utilization of photosynthate is critical to the ability of plants to sustain increased photosynthesis when grown at elevated [CO2].
KW - Carbon dioxide
KW - Climate change
KW - FACE
KW - Glycine max
KW - Photosynthesis
KW - Soybean
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U2 - 10.1016/j.agrformet.2003.09.002
DO - 10.1016/j.agrformet.2003.09.002
M3 - Article
AN - SCOPUS:1642289375
SN - 0168-1923
VL - 122
SP - 85
EP - 94
JO - Agricultural and Forest Meteorology
JF - Agricultural and Forest Meteorology
IS - 1-2
ER -