Abstract: 【Objective】In order to elucidate the regulation mechanism of potassium on plant nitrogen accumulation, translocation, grain protein and protein components formation. 【Method】Two winter wheat (Triticum Aestivum L.) cultivars differing in grain protein content, Ningmai 9 (low protein) and Yangmai 10 (medium protein) were grown to investigate the effects of different potassium rates on plant nitrogen accumulation, translocation of pre-anthesis nitrogen reserves, leaf potassium content at anthesis, and their relationships to the contents of grain protein and protein components.【Result】The potassium supply enhanced total protein content, but the effects of potassium on the contents of globulin and gliadin were significant whereas that was insignificant on glutenin content as compared with the non-potassium treatment. Thus, the ratio of Glu/Gli decreased markedly. Potassium fertilization very markedly enhanced pre-anthesis nitrogen accumulation and stored nitrogen translocation through increasing leaf potassium content at anthesis. Higher leaf potassium content at anthesis very significantly increased post-anthesis nitrogen accumulation of Yangmai 10, but for Ningmai 9, slightly. Compared with Ningmai 9, the role of potassium in raising the contents of grain protein and protein components was greater for Yangmai 10.【Conclusion】Under the experimental condition, the results suggest that post-anthesis nitrogen accumulation, which was very significantly increased by higher leaf potassium content at anthesis, is the vital physiological basis for determining grain protein formation of Yangmai 10, while pre-anthesis stored nitrogen translocation is for Ningmai 9, and the reasonable potassium rate for synchronously improved grain yield and quality of weak gluten wheat Ningmai 9 and medium gluten wheat Yangmai 10 could be K2O 150 and 225 kg·ha-1, respectively.

Key words: Winter wheat, Potassium rate, Nitrogen accumulation, Nitrogen transportation, Protein formation