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Title: WATER STRESS AND ELEVATED CO2 EFFECTS ON PHOTOSYNTHESIS AND GROWTH IN CORN

Author
item NIU, GENHUA - FAS-USDA
item Timlin, Dennis
item Reddy, Vangimalla
item Kim, Soo Hyung
item Gitz, Dennis

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 11/10/2003
Publication Date: 11/20/2003
Citation: Niu, G., Timlin, D.J., Reddy, V., Kim, S., Gitz, D.C. 2003. Water stress and elevated co2 effects on photosynthesis and growth in corn [abstract]. American Society of Agronomy Meetings. CDROM.

Interpretive Summary:

Technical Abstract: The effect of water stress imposed at vegetative and reproductive stages under ambient and elevated carbon dioxide conditions on the photosynthesis, evapo-transpiration, water use efficiency, and dry matter accumulation of corn plants (Zea mays L. cv. 34N43) was evaluated. Seeds were sowed on May 16 and were grown until R3 stage in outdoor SPAR (Soil-Plant-Atmosphere-Research) chambers where temperatures were maintained at 31/25 degree C (day/night) under ambient (370 umol mol -1) or elevated (750 umol mol -1) carbon dioxide concentrations. Water stress was imposed to ambient and high carbon dioxide chambers during vegetative (V10 to V16) and reproductive stage (VT to R1) stages by restricting irrigation. The canopy gross photosynthetic rates (Pg) of the plants were not affected by the two-week water stress under both carbon dioxide concentrations. Pg of plants under elevated carbon dioxide level was reduced by 12% at the end of the one-month water stress period compared to that of plants without water stress. Evapo-transpiration rates (ET) of plants under ambient carbon dioxide level decreased as water stress period extended, while ET of plants under elevated carbon dioxide condition did not respond to water stress. Water use efficiency of plants was increased under elevated carbon dioxide level. However, dry weight determined at R3 stage was not affected by water stress, regardless of carbon dioxide concentration.