Abstract: A pot experiment in the greenhouse was conducted with the variety “XR4347” of winter wheat in order to investigate the effect of rewatering/redrought stress after drought priming and nitrogen application on water use efficiency of winter wheat. The experiment included two nitrogen levels with no nitrogen (N0) and nitrogen fertilization (N1, 1.5g·pot1), and three water treatments under each nitrogen level consisting of full irrigation (CK), rewatering after drought priming (PW), and redrought stress after drought priming (PD). The results showed that redrought stress after drought priming decreased the water potential of plants. Compared with the CK and PW treatments, the reduction of stomatal conductance (gs) of PD treatment was greater than the reduction of net photosynthetic rate (Pn), and therefore, the water use efficiency at the leaf and plant level was improved. Under the CK and PW treatments, the Pn and gs of leaves were significantly increased under nitrogen fertilization compared with no nitrogen application, whereas the intrinsic water use efficiency (WUEint, Pn/gs) of leaves increased slightly. Under the PD treatment, the effect of nitrogen application on gs was greater than that on Pn. The Pn increased by 4.5% while gs decreased by 13.6%, and therefore, WUEint increased significantly. Furthermore, the PD treatment significantly reduced the gs and the water consumption under nitrogen fertilization, and the WUEb and leaf δ13C were the highest with nitrogen fertilization, further indicating that the higher WUEb of the PD treatment under nitrogen fertilization was due to the stomatal control. Therefore, in arid and water-deficient areas, the combination of drought priming and nitrogen fertilization can not only significantly reduce plant water consumption, save irrigation water, maintain crop growth and nutrient absorption, but also improve water use efficiency at the leaf and plant level.

Key words: Irrigation, Nutrient, Water stress, Stomatal conductance, Water potential, δ13C