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Title: FREE-AIR CO2 ENRICHMENT EFFECTS ON APEX DIMENSIONAL GROWTH OF SPRING WHEAT

Author
item LI, A - UNIV OF IDAHO, MOSCOW, ID
item Wall, Gerard - Gary
item TRENT, A - UNIV OF IDAHO, MOSCOW, ID
item HOU, Y - WSU, PULLMAN, WASHINGTON

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: The concentration of carbon dioxide (CO2) in the atmosphere is rising, which may affect future precipitation patterns and the water supply for the soil. Elevated CO2 has been known to increase the rate that plants use CO2 and to decrease the rate that they use water. A greater supply of the building blocks for growth will increase potential growth. Elevated CO2 increased the rate of elongation and widening of the shoots of spring whea grown in an open field under elevated CO2. Longer shoots did not have more spikes, but they did not have more sites where grain could grow. Because more florets were produced because of elevated CO2, grain production per acre is anticipated to be greater in a future high CO2 world assuming that CO2 does not adversely affect climate. This increase in yield will benefit both producers and end-users.

Technical Abstract: The CO2 concentration of the atmosphere is rising, which may affect potential growth of spring wheat (Triticum aestivum L). This study determined the rates of apical elongation and widening over the main stem and tillers in cv. Yecora Rojo grown under two levels of atmospheric CO2 concentration, 550 (elevated) or 370 (ambient) umol mol-1, in a free-air- CO2 enrichment (FACE) experiment conducted at the University of Arizona Maricopa Agricultural Research Center. Plants were sampled at different developmental stages and dissected to measure, with a stage micrometer, the length and widths of the apices of the main stem (MS), coleoptile (T0) and primary (T1,T2, and T3), and secondary tillers (T00, T01, T02, T10, T11, and T12). Elevated CO2 increased the apex lengths of T2 at the double ridge stage and of T3 and T10 at the double ridge and the terminal spikelet stages, and the apex widths of T2 at the double ridge stage and of T2, T3, T10, and T11 at the flag leaf appearance stage. Elevated CO2 changed apex elongation or widening within a plant by enhancing elongation or widening rates of the MS and later-formed tillers. Early-formed tillers were less responsive to elevated CO2 levels. These results have enabled us to better predict wheat apical development and grain production in the elevated CO2 environment of the future.