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Title: EFFECTS OF FREE-AIR CO2 ENRICHMENT AND NITROGEN STRESS ON WHEAT GAS EXCHANGE AND CANOPY ARCHITECTURE

Author
item BROOKS, T - UNIV OF ARIZONA
item Wall, Gerard - Gary
item Pinter Jr, Paul
item Kimball, Bruce
item Adam, Neal
item LEE, T - USDA-ARS, USWCL
item La Morte, Robert
item LEAVITT, S - UNIV OF ARIZONA

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/28/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Hard red spring wheat (Triticum aestivum L. cv. Yecora Rojo) was grown in the field and exposed to two CO2 regimes, ambient (C) (370 umol/mol) and ambient +200 umol/mol (F) during 1995-96 and 1996-97. Half of each CO2 treatment was supplemented with 70 kgN/ha (L), the other half supplied supplied with 350 kgN/ha (H). Daily total carbon accumulation rates (determined at five growth stages) for uppermost fully expanded sunlit leaves were 30% greater in FH compared with CL, while FL and CH were were intermediate in their response. In contrast, whole-canopy total carbon accumulation differed by only 15% when FH was compared with CL. Treatment difference in whole-canopy total carbon accumulation agreed with final grain yields. Vertical leaf nitrogen profiles, degree of erectophile leaf growth, and changes in canopy density (as evidenced by measurements of canopy vertical greenness profiles, plant area index, and mean leaf tip angle distribution) may explain the 15% decrease in treatment response between the whole-canopy and single leaves.