, Volume 5, Issue 9, pp 368–368 | Cite as

Bemerkungen zur Mitteilung von E. H. Reinau: Zur CO2-Resttheorie im Pflanzenbau

  • E. K. Gabrielsen
Kurze Mitteilungen Disputanda


In a brief communication to “Nature”1 I have introduced the term “Threshold Value” to design the lowest carbon dioxide concentration in the atmosphere at which photosynthesis of green leaves can take place. The final proof for the existence of this threshold is found in my experiments with leaves exposed to high light intensities in air poor in carbon dioxide1,2. These experiments show that respiratory carbon dioxide is expired until the threshold value for photosynthesis is reached at 0.0090 vol. %. To avoid confusion it is considered best to use the term “Threshold Value” only in the sense stated above.Reinau's use of the term to designate equilibria between consumption and production of carbon dioxide, found in the open air, seems to be without any adequate basis.


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    E. H. Reinau, Gartenbauwissenschaft3, 101 (1930).Google Scholar
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    E. S. Miller undG. O. Burr, Plant Physiol.10, 73 (1935).Google Scholar

Copyright information

© Birkhäuser Verlag 1949

Authors and Affiliations

  • E. K. Gabrielsen
    • 1
  1. 1.Pflanzenphysiologisches Laboratorium, Königl. Tierärztliche und Landwirtschaftliche HochschuleKopenhagen

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