{
  "abstract": "C3-C4 intermediate (C2) plants decarboxylate photorespiratory glycine in the bundle sheath, where Rubisco refixes some of the released CO2, yet researchers analyze their gas exchange with methods built for C3 leaves. I calibrated the C3-C4 model of von Caemmerer against published compensation points and Laisk measurements on C3 and C2 Flaveria and relatives at 36 {degrees}C, and analyzed the resulting leaf as an experimenter would. With its true Rubisco kinetics and mesophyll conductance, Farquhar-von Caemmerer-Berry fits described its CO2 response closely but returned a day respiration (Rd) of -5.4 mol m-2 s-1 against a true 1.2, and underestimated maximum carboxylation and electron transport rates by 12% and 11%. The Rd deficit equaled net bundle-sheath CO2 fixation where mesophyll CO2 equals the photorespiratory compensation point ({Gamma}*), within 5.3% in every leaf. The Laisk method gave {Gamma}* = 42 bar after mesophyll correction, compared with a true 65 bar, and the oxygen-slope method overestimated Rubisco specificity by 26-53%. Published curves of two C3-C4 Moricandia species returned Rd of -2.5 mol m-2 s-1, and their C3 congener 1.1. An Rd well below that of C3 relatives fitted the same way, signaling bundle-sheath refixation, not a fitting failure.",
  "abstract_shown": true,
  "affiliations": [
    "Kahramanmaras Sutcu Imam Universitesi"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "E. Yazar"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/88fn4v31tpzbz.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.12.758566",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758566v1.full",
  "id": "88fn4v31tpzbz",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758566v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "plant biology"
    ],
    [
      "openalex",
      "1312|Photosynthetic Processes and Mechanisms"
    ]
  ],
  "openalex": "W7222485093",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758566v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-12",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/88fn4v31tpzbz.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:28:02Z",
      "native_id": "10.64898/2026.10.12.758566",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758566v1"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "biorxiv:plant biology",
      "subfield": "plant-biology"
    }
  ],
  "title": "C3 gas-exchange analyses read bundle-sheath refixation in C3-C4 intermediate leaves as negative day respiration",
  "title_text": "C3 gas-exchange analyses read bundle-sheath refixation in C3-C4 intermediate leaves as negative day respiration",
  "type": "preprint",
  "updated_at": "2026-10-30T12:28:02Z",
  "url": "https://research.draconitic.com/paper/88fn4v31tpzbz",
  "venue": "bioRxiv",
  "versions": []
}