About Us | Help Videos | Contact Us | Subscriptions



This article in CS

  1. Vol. 31 No. 6, p. 1611-1615
    Received: Jan 9, 1991

    * Corresponding author(s):
Request Permissions


Carbon Isotope Discrimination and Transpiration Efficiency in Common Bean

  1. James R. Ehleringer ,
  2. Stephen Klasen,
  3. Creed Clayton,
  4. Dorothy Sherrill,
  5. Mindy Fuller-Holbrook,
  6. Fu Qing-nong and
  7. Tamsie A. Cooper
  1. Dep. of Biology and Stable Isotope Ratio Facility for Environmental Res., Univ. of Utah, Saltl Lake City, UT 84112.



Carbon isotope discrimination (Δ) values were measured in diverse genetic lines of common bean (Phaseolus vulgaris L.) as indicators of water-use efficiency. Using on-line Δ measurements, there was a close agreement between observed Δ values and those predicted by C3-photosynthesis Δ models. Additionally, Δ values were also significantly correlated with transpiration efficiency estimates (W) measured in potted plants grown outdoors on a long-term basis. Based on ancestral race and domestication center, there were no significant differences in W or Δ. However, differences occurred when cultivars were analyzed on the basis of the geographic region for which they had been developed. On average, lines developed for Central and South America exhibited significantly higher W values (0.63 vs. 0.57 mmol mol-1, respectively) and lower Δ values (21.07 vs. 21.51‰, respectively) than did lines developed for North America. There were also small, but significant differences in the slopes of the relations between Δ and W that were dependent on the geographic region for which lines had been developed. North American common bean lines exhibited a steeper relationship between these two parameters than did Central-South American lines. The basis for these apparent differences in transpiration efficiency is unclear, but may have been associated with variation in leaf conductances or paraheliotropic leaf movements among the two groups.

Supported by the Competitive Res. Grants Office at the USDA.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © .