Using three wheat cultivars (Triticum aestivum L. ) , Een1, Huamai8 and 95A-10, which exhibit different grain filling characters. the relationship of ultrastructure of the chalazal cells in wheat caryop-sis and grain filling was studied. The results indicate that the lipoid and polysaccharide deposited in vacuoles of the chalazal cells have no obvious inhibitory actions to the grain filling. It appears that a direct relationship exists between the proceeding and end time of grain filling and the amount and appearing time of the lipoid, within lignin and suberin deposited on the inner wall of chalazal cells, and between grain filling rate and cultivars characteristic. The appearing time of the lipoid, within lignin and suberin deposited on the inner wall of chalazal cells in cultivar with large grain (Eenl and 95A-10) was later than that in cultivar with small grain (Huamai8), and the amount of deposits in the former was less than that in the latter. The late development of caryopsis and low rate of grai The relationship of ultrastructure of the chalazal cells in wheat caryop-sis and grain filling was studied. The results indicate that the lipoid and polysaccharide deposited in vacuoles of the chalazal cells have no obvious inhibitory actions to the grain filling. It appears that a direct relationship exists between the proceeding and end time of grain filling and the amount and appearing time of the lipoid, within lignin and suberin deposited on the inner wall of chalazal cells, and between grain filling rate and cultivars characteristic. The appearing time of the lipoid, within lignin and suberin deposited on the inner wall of chalazal cells in cultivar with large grain (Eenl and 95A-10) was later than that in cultivar with small grain (Huamai 8), and the amount of deposits in the former was less than that in the latter. The late development of caryopsis an d low rate of grai