Moderate intermittent water deficit enhances dry matter remobilization, nitrogen uptake, and water and nitrogen use efficiency in winter wheat

Drought stress severely inhibits the growth and production of winter wheat, particularly after anthesis. To mitigate these effects, this study evaluated the impact of intermittent water deficit priming on physiological and yield-related traits of winter wheat under subsequent drought stress, based on a two-year experiment. Intermittent moderate water deficit priming (PID2) significantly increased photosynthetic rate (P_n) and stomatal conductance, resulting in higher dry matter accumulation and relative growth rate. Moreover, compared to non-primed plants, PID2 improved dry matter translocation efficiency and its contribution to grain by 42.3 ​% and 23.0 ​%, respectively, thereby increasing yield by 27.1 ​%. Additionally, PID2 and persistent mild water deficit priming (PPD1) improved root distribution in the middle and lower soil layers, enhancing nitrogen uptake, as well as grain nitrogen and protein accumulation. Nitrogen use efficiency for yield under PID2 and PPD1 treatments increased by 12.5 ​% and 12.2 ​%, respectively, compared to non-primed plants. The TOPSIS assessment indicated that PID2 enhanced drought tolerance in wheat most effectively, making it a promising water management strategy for mitigating post-anthesis stress.