{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T01:18:21Z","timestamp":1787015901540,"version":"build-2736575974"},"reference-count":69,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2025,9,29]],"date-time":"2025-09-29T00:00:00Z","timestamp":1759104000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Plant Cell &amp;amp; Environment"],"published-print":{"date-parts":[[2026,1]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    During photosynthesis, CO\u2082 uptake is counterbalanced by concurrent CO\u2082\u2010releasing processes, complicating the interpretation of gas exchange measurements. While photorespiration accounts for a significant portion of this CO\u2082 release, emerging evidence indicates that there are additional metabolic pathways that release CO\n                    <jats:sub>2<\/jats:sub>\n                    during photosynthesis. This metabolism\u2014termed day respiration (often\n                    <jats:italic>R<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>d<\/jats:italic>\n                    <\/jats:sub>\n                    ) or respiration in the light (\n                    <jats:italic>R<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>L<\/jats:italic>\n                    <\/jats:sub>\n                    )\u2014is now recognized as an independent and significant source of CO\n                    <jats:sub>2<\/jats:sub>\n                    emission during photosynthesis. Here we revisit classical models of photosynthesis and incorporate new insights from isotopic labeling and metabolic flux analysis (MFA) to investigate the biochemical basis of\n                    <jats:italic>R<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>L<\/jats:italic>\n                    <\/jats:sub>\n                    . We identified the cytosolic glucose\u20106\u2010phosphate (G6P) shunt through the oxidative pentose phosphate pathway (OPPP) as the predominant contributor to\n                    <jats:italic>R<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>L<\/jats:italic>\n                    <\/jats:sub>\n                    . This shunt explains some long\u2010standing anomalies in Calvin\u2010Benson\u2010Bassham (CBB) cycle labeling. Under non\u2010stressed conditions,\n                    <jats:italic>R<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>L<\/jats:italic>\n                    <\/jats:sub>\n                    remains stable across varying CO\u2082 concentrations and light intensities. Under heat stress,\n                    <jats:italic>R<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>L<\/jats:italic>\n                    <\/jats:sub>\n                    shifts toward a plastidial source. Together, these findings resolve longstanding questions about carbon flux during photosynthesis and improve our understanding of\n                    <jats:italic>R<\/jats:italic>\n                    <jats:sub>\n                      <jats:italic>L<\/jats:italic>\n                    <\/jats:sub>\n                    by explaining its metabolic origin, physiological significance in carbon balance during photosynthesis, and regulation under varying environmental conditions.\n                  <\/jats:p>","DOI":"10.1111\/pce.70216","type":"journal-article","created":{"date-parts":[[2025,9,30]],"date-time":"2025-09-30T05:54:17Z","timestamp":1759211657000},"page":"309-319","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Carbon Dioxide Release During Photosynthesis: Connecting Gas Exchange Behavior With Biochemistry"],"prefix":"10.1111","volume":"49","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4423-3223","authenticated-orcid":false,"given":"Thomas D.","family":"Sharkey","sequence":"first","affiliation":[{"name":"Department of Biochemistry Michigan State University East Lansing Michigan USA"},{"name":"MSU\u2010DOE Plant Research Laboratory Michigan State University East Lansing Michigan USA"},{"name":"MSU Plant Resilience Institute Michigan State University East Lansing Michigan USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8259-2315","authenticated-orcid":false,"given":"Yuan","family":"Xu","sequence":"additional","affiliation":[{"name":"Department of Biochemistry Michigan State University East Lansing Michigan USA"},{"name":"MSU\u2010DOE Plant Research Laboratory Michigan State University East Lansing Michigan USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,9,29]]},"reference":[{"key":"e_1_2_16_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.copbio.2019.11.003"},{"key":"e_1_2_16_3_1","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.arplant.55.031903.141701"},{"key":"e_1_2_16_4_1","doi-asserted-by":"publisher","DOI":"10.1093\/jxb\/erw414"},{"key":"e_1_2_16_5_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2008824117"},{"key":"e_1_2_16_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/0006-291X(71)90475-X"},{"key":"e_1_2_16_7_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41477-017-0065-x"},{"key":"e_1_2_16_8_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF00384257"},{"key":"e_1_2_16_9_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF02139287"},{"key":"e_1_2_16_10_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.30.1.82"},{"key":"e_1_2_16_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/0304-4165(85)90004-2"},{"key":"e_1_2_16_12_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.010576"},{"key":"e_1_2_16_13_1","doi-asserted-by":"publisher","DOI":"10.1111\/nph.15872"},{"key":"e_1_2_16_14_1","doi-asserted-by":"publisher","DOI":"10.1016\/0003-9861(79)90052-3"},{"key":"e_1_2_16_15_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF00386231"},{"key":"e_1_2_16_16_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.17.00601"},{"key":"e_1_2_16_17_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41477-022-01294-9"},{"key":"e_1_2_16_18_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.83.2.399"},{"key":"e_1_2_16_19_1","doi-asserted-by":"publisher","DOI":"10.1111\/nph.15126"},{"key":"e_1_2_16_20_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-0716-3802-6_9"},{"key":"e_1_2_16_21_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF00035838"},{"key":"e_1_2_16_22_1","doi-asserted-by":"publisher","DOI":"10.1093\/jxb\/erp374"},{"key":"e_1_2_16_23_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.103.025676"},{"key":"e_1_2_16_24_1","doi-asserted-by":"publisher","DOI":"10.1093\/treephys\/tpy103"},{"key":"e_1_2_16_25_1","doi-asserted-by":"publisher","DOI":"10.3389\/fpls.2018.01461"},{"key":"e_1_2_16_26_1","doi-asserted-by":"publisher","DOI":"10.1093\/plphys\/kiac162"},{"key":"e_1_2_16_27_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.43.6.902"},{"key":"e_1_2_16_28_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.58.4.552"},{"key":"e_1_2_16_29_1","first-page":"1","article-title":"A Critical Consideration of the Quantum Yield of Chlorella Photosynthesis","volume":"13","author":"Kok B.","year":"1948","journal-title":"Enzymologia"},{"key":"e_1_2_16_30_1","doi-asserted-by":"publisher","DOI":"10.1016\/S1369-5266(03)00039-6"},{"key":"e_1_2_16_31_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.54.5.678"},{"key":"e_1_2_16_32_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.76.3.723"},{"key":"e_1_2_16_33_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1319485111"},{"key":"e_1_2_16_34_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF00384922"},{"key":"e_1_2_16_35_1","doi-asserted-by":"publisher","DOI":"10.1016\/0005-2744(69)90420-3"},{"key":"e_1_2_16_36_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.110.154443"},{"key":"e_1_2_16_37_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.75.1.298"},{"key":"e_1_2_16_38_1","volume-title":"The Maximum Quantum Yield Controversy Otto Warburg and the \u201cMidwest\u2010Gang\u201d","author":"Nickelsen K.","year":"2011"},{"key":"e_1_2_16_39_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.104.055566"},{"key":"e_1_2_16_40_1","doi-asserted-by":"publisher","DOI":"10.1093\/jxb\/ern002"},{"key":"e_1_2_16_41_1","doi-asserted-by":"publisher","DOI":"10.1038\/newbio230159a0"},{"key":"e_1_2_16_42_1","doi-asserted-by":"publisher","DOI":"10.1042\/BCJ20190234"},{"key":"e_1_2_16_43_1","doi-asserted-by":"publisher","DOI":"10.5962\/bhl.title.5714"},{"key":"e_1_2_16_44_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11120-018-0583-z"},{"key":"e_1_2_16_45_1","doi-asserted-by":"publisher","DOI":"10.1016\/0003-9861(89)90441-4"},{"key":"e_1_2_16_46_1","doi-asserted-by":"publisher","DOI":"10.1093\/plphys\/kiad305"},{"key":"e_1_2_16_47_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-0716-3802-6_12"},{"key":"e_1_2_16_48_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.78.1.71"},{"key":"e_1_2_16_49_1","doi-asserted-by":"publisher","DOI":"10.1042\/BCJ20200480"},{"key":"e_1_2_16_50_1","doi-asserted-by":"publisher","DOI":"10.19103\/AS.2022.0119.13"},{"key":"e_1_2_16_51_1","doi-asserted-by":"publisher","DOI":"10.1093\/jxb\/erv484"},{"key":"e_1_2_16_52_1","doi-asserted-by":"publisher","DOI":"10.1104\/pp.125.1.20"},{"key":"e_1_2_16_53_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.0031-9317.2005.00582.x"},{"key":"e_1_2_16_54_1","doi-asserted-by":"publisher","DOI":"10.1105\/tpc.112.106989"},{"key":"e_1_2_16_55_1","doi-asserted-by":"publisher","DOI":"10.1111\/nph.14816"},{"key":"e_1_2_16_56_1","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.pp.22.060171.000401"},{"key":"e_1_2_16_57_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.phytochem.2007.04.023"},{"key":"e_1_2_16_58_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-313X.2004.02293.x"},{"key":"e_1_2_16_59_1","doi-asserted-by":"publisher","DOI":"10.1111\/pce.14949"},{"key":"e_1_2_16_60_1","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.272.43.26985"},{"key":"e_1_2_16_61_1","doi-asserted-by":"publisher","DOI":"10.1111\/pbi.12002"},{"key":"e_1_2_16_62_1","doi-asserted-by":"publisher","DOI":"10.1093\/plphys\/kiab076"},{"key":"e_1_2_16_63_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-025-88574-4"},{"key":"e_1_2_16_64_1","doi-asserted-by":"publisher","DOI":"10.1093\/plphys\/kiad507"},{"key":"e_1_2_16_65_1","doi-asserted-by":"publisher","DOI":"10.1111\/nph.19730"},{"key":"e_1_2_16_66_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2121531119"},{"key":"e_1_2_16_67_1","doi-asserted-by":"publisher","DOI":"10.1111\/nph.19330"},{"key":"e_1_2_16_68_1","doi-asserted-by":"publisher","DOI":"10.1111\/pce.14070"},{"key":"e_1_2_16_69_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-3040.2009.01934.x"},{"key":"e_1_2_16_70_1","doi-asserted-by":"publisher","DOI":"10.1093\/jxb\/err038"}],"container-title":["Plant, Cell &amp; Environment"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/pce.70216","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,29]],"date-time":"2025-12-29T14:09:16Z","timestamp":1767017356000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/pce.70216"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,9,29]]},"references-count":69,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2026,1]]}},"alternative-id":["10.1111\/pce.70216"],"URL":"https:\/\/doi.org\/10.1111\/pce.70216","archive":["Portico"],"relation":{"has-preprint":[{"id-type":"doi","id":"10.22541\/au.175022848.87886138\/v1","asserted-by":"object"}]},"ISSN":["0140-7791","1365-3040"],"issn-type":[{"value":"0140-7791","type":"print"},{"value":"1365-3040","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,9,29]]},"assertion":[{"value":"2025-06-17","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-09-17","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-09-29","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}