Flag leaves have been considered to be the first key organ contributing to higher yields in triticeae crops. Therefore, dynamical changes in physiological metabolisms in flag leaves are important to regulate senescence and provide reserves to the developing grains. In this study, the dynamic changes in contents of metabolites in flag leaves during grain filling of wheat (Triticum aestivum L.) were analyzed using non-targeted liquid chromatography–mass spectrometry. Metabolic profiling was conducted at Zadoks 69, Zadoks 75, Zadoks 83 and Zadoks 87 stages. In total, 126 metabolites were annotated over the grain-filling period. Metabolic analysis showed that the annotated metabolites were involved in the carbon and nitrogen metabolisms, regulation of senescence, antioxidant metabolism to resist mainly drought and hot stresses. In the metabolic pathway of carbohydrate metabolism, glucose, gluconic acid and pyruvate changed significantly during grain filling; in the amino acid (AA) metabolism, most AAs annotated showed the highest concentrations at the anthesis or Zadoks 75 stages and then gradually decreased; and α-Linolenic acid metabolism pathway may be involved in the modification of leaf mechanical strength, extension angle and light reception for photosynthesis; generally, the jasmonate content was gradually increased, showing the highest values at the Zadoks 87 stage; whereas the high content of phenols was observed at earlier two stages, followed by a gradually decrease. Based on the analysis on the functions of annotated metabolites, we conclude that these pathways might be of very importance for wheat to construct stress-resistant metabolism, regulate leaf senescence and remobilization of leaf reserves to filling grain.

旗叶被认为是促成小麦科作物高产的第一个关键器官。因此，旗叶生理代谢的动态变化对于调节衰老和为发育中的籽粒提供储备很重要。在这项研究中，动态籽粒灌浆（期间在旗叶代谢物的含量改变小麦L.) 使用非靶向液相色谱-质谱法进行分析。在 Zadoks 69、Zadoks 75、Zadoks 83 和 Zadoks 87 阶段进行代谢分析。在籽粒灌浆期间总共注释了 126 种代谢物。代谢分析表明，注释的代谢物参与碳和氮代谢、衰老调节、抗氧化代谢，主要抵抗干旱和热胁迫。在碳水化合物代谢途径中，灌浆过程中葡萄糖、葡萄糖酸和丙酮酸发生显着变化；在氨基酸（AA）代谢中，大部分AA在开花期或Zadoks 75期浓度最高，然后逐渐降低；α-亚麻酸代谢途径可能参与叶片机械强度的改变，光合作用的伸展角和光接收；总体而言，茉莉酸含量逐渐增加，在Zadoks 87阶段表现出最高值；而在前两个阶段观察到高含量的酚类，随后逐渐减少。基于对注释代谢物功能的分析，我们得出结论，这些途径可能对小麦构建抗逆代谢、调节叶片衰老和叶片储备再动员到灌浆中具有重要意义。