title: Varying Response of the Concentration and Yield of Soybean Seed Mineral Elements, Carbohydrates, Organic Acids, Amino Acids, Protein, and Oil to Phosphorus Starvation and CO2Enrichment.
abstract: A detailed investigation of the concentration (e.g., mg g-1seed) and total yield (e.g., g plant-1) of seed mineral elements and metabolic profile under phosphorus (P) starvation at ambient (aCO2) and elevated carbon dioxide (eCO2) in soybean is limited. Soybean plants were grown in a controlled environment at either sufficient (0.50 mM P, control) or deficient (0.10 and 0.01 mM, P-stress) levels of P under aCO2and eCO2(400 and 800 μmol mol-1, respectively). Both the concentration and yield of 36 out of 38 seed components responded to P treatment and on average 25 and 11 components increased and decreased, respectively, in response to P starvation. Concentrations of carbohydrates (e.g., glucose, sugar alcohols), organic acids (e.g., succinate, glycerate) and amino acids increased while oil, and several minerals declined under P deficiency. However, the yield of the majority of seed components declined except several amino acids (e.g., phenylalanine, serine) under P deficiency. The concentration-based relationship between seed protein and oil was negative (r2= 0.96), whereas yield-based relationship was positive (r2= 0.99) across treatments. The CO2treatment also altered the concentration of 28 out of 38 seed components, of which 23 showed decreasing (e.g., sucrose, glucose, citrate, aconitate, several minerals, and amino acids) while C, iron, Mn, glycerate, and oil showed increasing trends at eCO2. Despite a decreased concentration, yields of the majority of seed components were increased in response to eCO2, which was attributable to the increased seed production especially near sufficient P nutrition. The P × CO2interactions for the concentration of amino acids and the yield of several components were due to the lack of their response to eCO2under control or the severe P starvation, respectively. Thus, P deficiency primarily reduced the concentration of oil and mineral elements but enhanced a majority of other components. However, seed components yield consistently declined under P starvation except for several amino acids. The study highlighted a P nutritional-status dependent response of soybean seed components to eCO2suggesting the requirement of an adequate P supply to obtain the beneficial effects of eCO2on the overall yield of various seed components.
authors.affiliation: Crop Systems and Global Change Laboratory, United States Department of Agriculture - Agricultural Research Service, BeltsvilleMD, USA; Wye Research and Education Center, University of Maryland, College Park, College ParkMD, USA.
authors.forename: Shardendu K
authors.initials: SK
authors.lastname: Singh
authors.affiliation: Crop Systems and Global Change Laboratory, United States Department of Agriculture - Agricultural Research Service, Beltsville MD, USA.
authors.forename: Jinyoung Y
authors.initials: JY
authors.lastname: Barnaby
authors.affiliation: Crop Systems and Global Change Laboratory, United States Department of Agriculture - Agricultural Research Service, Beltsville MD, USA.
authors.forename: Vangimalla R
authors.initials: VR
authors.lastname: Reddy
authors.affiliation: Crop Systems and Global Change Laboratory, United States Department of Agriculture - Agricultural Research Service, Beltsville MD, USA.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Sicher
keywords: contents; glycerate; myo-inositol; phytic acid; pinitol; proline; putrescine