Effects of elevated CO2 concentration on growth and water use efficiency of winter wheat under two soil water regimes |
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Authors: | Yunzhou Qiao Baodi Dong Yuxin Li Mengyu Liu |
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Institution: | a Key Laboratory of Agricultural Water Resources & Hebei Key Laboratory of Agricultural Water-Saving, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang 050021, PR China b School of Pharmaceutical and Chemical Engineering, Taizhou University, Linhai Zhejiang 317000, PR China c Department of Chemistry, Shijiazhuang University, Shijiazhuang 050021, PR China |
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Abstract: | Winter wheat (Triticum aestivum L. cv. Kenong9204) was grown in open top chambers with either ambient or elevated CO2 concentrations (358 ± 19 μmol mol−1 or 712 ± 22 μmol mol−1, respectively) in well-watered or drought conditions. Although elevated CO2 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 CO2 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 CO2 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 CO2 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 CO2 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 CO2 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 CO2 concentration rises. |
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Keywords: | OTC open top chamber FACE free-air CO2 enrichment RSR root/shoot ratio RLD root length density GY grain yield WUE water use efficiency SWD soil water depletion HI harvest index ET total water consumption evapotranspiration |
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