Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 28, 1997
Publication Date: N/A
Hard red spring wheat (Triticum aestivum L. cv. Yecora Rojo) was field- grown in CO2 concentration of ambient (370 umol/mol) air (Control: C) and air enriched to 200 umol/mol above ambient using a free-air CO2 enrichment (Face: F) apparatus (main plot) during 1995-6 and 1996-7. A high (H) and low (L) level of nitrogen was applied to each half of the main CO2 treatments at levels of 350 and 70 kg/ha, respectively (split- plot). Daily totals of leaf photosynthesis were consistently greater in FH compared with CL, whereas FL and CH were intermediate in their response throughout the 5-leaf, tillering, stem-elongation, anthesis, grain-fill and dough-ripe growth stages. As nitrogen stress developed, the proportionate change in daily photosynthesis between high and low nitrogen was consistently greater in Face compared with Control. Significant two-way interaction (CO2xN) was observed at grain fill (p>F, 0.14) and stem-elongation (p>F, 0.03) during 1996 and 1997, respectively. Preliminary results suggest that acclimation of the photosynthetic apparatus to elevated CO2 may have occurred in wheat grown under nitrogen deficiency.