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Title: Influence of daily carbon dioxide exposure duration and root environment on soybean response to elevated carbon dioxide

Journal Article · · Journal of Environmental Quality
; ; ;  [1];  [2]
  1. USDA-ARS, Raleigh, NC (United States). Air Quality-Plant Growth and Development Research Unit
  2. North Carolina State Univ., Raleigh, NC (United States). Dept. of Statistics

Little is known about effects of daily CO{sub 2} enrichment duration and root environment on plant response to elevated CO{sub 2}. Two experiments were performed with Essex soybean (Glycine max L. Merr.) in open-top field chambers to address these questions. In one experiment, effects of 12 and 24 h d{sup {minus}1} exposures to double-ambient CO{sub 2} were compared for plants grown in 14 L pots that were either insulated to moderate soil temperature or not insulated. Although never significant statistically, trends at some growth stages suggested that nighttime CO{sub 2} enrichment contributed to growth and yield. Plants grew and yielded more in insulated than noninsulated pots, but there were no significant CO{sub 2} enrichment {times} insulation interactions. In the second experiment, response to approximately 1.3, 1.6, and 1.9 times ambient CO{sub 2} was compared for plants grown in the ground or 14 L pots. Enhancement of photosynthesis, growth, and yield by CO{sub 2} enrichment was similar in pots and in the ground. Linear responses to different CO{sub 2} concentrations were significant for all yield components in both root environments, whereas quadratic responses were significant for plants in pots but not for plants in the ground. Tests of proportionality of response for yield components showed no evidence of significant differences between plants in pots and in the ground except weight per 100 seeds. Seed yield enhancement at 1.9 times ambient CO{sub 2} was 36% for plants in pots and 33% for plants in the ground. Overall, proportional response of soybean to CO{sub 2} enrichment was relatively uniform in spite of large differences in baseline growth and yield.

Sponsoring Organization:
USDOE
OSTI ID:
678080
Journal Information:
Journal of Environmental Quality, Vol. 28, Issue 2; Other Information: PBD: Mar-Apr 1999
Country of Publication:
United States
Language:
English