Wheat cultivars Yannong 19,Yangmai 16,and Ningmai 13 responsible for strong-,medium-,and weak-gluten types respectively,were used to compare the accumulations of starch and protein during grain filling as well as the amyloplast components in mature grains.The contents of starch,amylose,and amlylopectin in grains showed similar dynamic changes in the three cultivars,and ranked as Ningmai 13Yangmai 16Yangnong 19.The accumulation quantities of starch,amylose,and amlylopectin varied in trends of S-curve during the grain-filling period,and the accumulation rate was in a parabola.Among the three cultivars,Yangnong 19 possessed the highest quantity and rate in the accumulation of starch and its components,and Ningmai 13 the lowest.The changes of protein content during grain filling in three cultivars all presented V-curves with the highest content in Yannong 19 and the lowest content in Ningmai 13.During the development of grains,large amyloplast formed in earlier period and small amyloplast was observed mainly in later period.The quantity of large amyloplast in the three cultivars showed Yannong 19Yangmai 16Ningmai 13,whereas those of small amyloplast randed in the opposite direction.In endosperm cells of mature grain,large amyloplast was more than small amyloplast in Yannong 19,and the amyloplasts were in compact structures.In Ningmai 13,the opposite status was observed.