Foliar nitrogen(N)application is an effective strategy to improve protein content and quality in wheat kernels,but the specific effects of N forms remain unclear.In a two-year field study,foliar application of various N forms(NO3-,urea,NH4+)at anthesis was performed to measure their effects on wheat grain protein accumulation,quality formation,and the underlying mechanisms.Foliar application of three N forms showed varying effects in improving grain gluten proteins and quality traits.Under NH4+applica-tion,there was more post-anthesis N uptake for grain filling,with relatively strong increase in enzyme activities and gene expression associated with N metabolism in flag leaves at 8-20 days after anthesis(DAA),whereas its promotion of grain N metabolism became weaker after 20 DAA than those under NO3 and urea treatments.More N was remobilized from source organs to grain under treatment with foliar NO3 and urea.Genes controlling the synthesis of gluten protein and disulfide bonds were upregu-lated by NO3 and urea at 20-28 DAA,contributing to increased grain protein content and quality.Overall,foliar applications of NO3 and urea were more effective than those of NH4+in increasing grain N filling.These findings show that manipulating the source-sink relationship by reinforcing grain N metabolism and N remobilization is critical for optimizing grain protein accumulation and quality formation.

Xiaokang Lyu;Yang Liu;Na Li;Liban Ku;Yuting Hou;Xiaoxia Wen

College of Agronomy,Northwest A&F University,Yangling 712100,Shaanxi,China

作物学报（英文版）

[1]Xiaokang Lyu;Yang Liu;Na Li;Liban Ku;Yuting Hou;Xiaoxia Wen-.Foliar applications of various nitrogen(N)forms to winter wheat affect grain protein accumulation and quality via N metabolism and remobilization)[J].作物学报（英文版）,2022(04):1165-1177

NH4+applica,remobilized

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