摘要
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Winter wheat (<i>Triticum aestivum</i> L. cv. Kenong9204) was grown in open top chambers with either ambient or elevated CO<sub>2</sub> concentrations (358+or-19 micro mol mol<sup>-1</sup> or 712+or-22 micro mol mol<sup>-1</sup>, ...
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Winter wheat (<i>Triticum aestivum</i> L. cv. Kenong9204) was grown in open top chambers with either ambient or elevated CO<sub>2</sub> concentrations (358+or-19 micro mol mol<sup>-1</sup> or 712+or-22 micro mol mol<sup>-1</sup>, respectively) in well-watered or drought conditions. Although elevated CO<sub>2</sub> did not significantly affect the height of the plants at harvest, it significantly increased the aboveground biomass by 10.1% and the root/shoot ratio by 16.0%. Elevated CO<sub>2</sub> also significantly increased the grain yield (GY) by 6.7% when well-watered and by 10.4% when drought stressed. Specifically, in the well-watered condition, this increase was due to a greater number of ears (8.7% more) and kernels (8.6). In the drought condition, it was only due to a greater number of spikes (17.1% more). In addition, elevated CO<sub>2</sub> also significantly increased the water use efficiency (WUE) of the plants by 9.9% when well-watered and by 13.8% under drought conditions, even though the evapotranspiration (ET) of the plants did not change significantly. Elevated CO<sub>2</sub> also significantly increased the root length in the top half of the soil profile by 35.4% when well-watered and by 44.7% under drought conditions. Finally, elevated CO<sub>2</sub> significantly increased the root water uptake by 52.9% when well-watered and by 10.1% under drought conditions. These results suggest that (1) future increases in atmospheric CO<sub>2</sub> concentration may have a significant effect on wheat production in arid and semiarid areas where wheat cultivation requires upland cropping or deficit irrigation; (2) wheat cultivars can be developed to have more tillers and kernels through selective breeding and field management; and (3) fertilizer and water management in topsoil will become increasingly important as atmospheric CO<sub>2</sub> concentration rises.
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