Photosynthesis Research

, Volume 6, Issue 4, pp 289–294

Errors in differential infrared carbon dioxide analysis resulting from water vapor

  • James A. Bunce
  • David A. Ward
Technical Communication

DOI: 10.1007/BF00054104

Cite this article as:
Bunce, J.A. & Ward, D.A. Photosynth Res (1985) 6: 289. doi:10.1007/BF00054104


Water vapor was added differentially to the gas streams entering the cells of three makes of differential infrared carbon dioxide analysers. Analyser deflections were compared with those expected from dilution of the carbon dioxide by the additional gas. Tests were made at 0, 365, and 730 cm3 m−3 concentrations of carbon dioxide, and with the dewpoint in one cell of the analysers held constant at 15, 20, or 25°C. None of the analysers always responded in the ways predicted from dilution. The results showed that errors of a few cm3 m−3 could occur in estimates of carbon dioxide differentials using the theoretical correction for dilution. Furthermore the amount of error varied with the carbon dioxide range, the difference in water content, and in some cases the dewpoint range.

Key words

carbon dioxide uptake gas exchange infra-red gas analysis photosynthesis 

Copyright information

© Martinus Nijhoff/Dr W. Junk Publishers 1985

Authors and Affiliations

  • James A. Bunce
    • 1
  • David A. Ward
    • 1
  1. 1.Light and Plant Growth Laboratory, USDA-ARSBeltsville Agricultural Research CenterBeltsvilleUSA