Using three wheat cultivars (Triticum aestivum L. ), Een1, Huamai8 and 95A-10, which ex-hibit 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 vacuolesof the chalazal cells have no obvious inhibitory actions to the grain filling. It appears that a direct relationshipexists 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 culti-vars characteristic. The appearing time of the lipoid, within lignin and suberin deposited on the inner wall ofchalazal cells in cultivar with large grain (Een1 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 ofcaryopsis and low rate of grain filling account for the wrinkled grain of 95A-10. The transport of assimilatesin chalazal cells coexists with symplastic and apoplastic pathways, but symplastic pathway plays a major roleafter 24 days of flowering.
ZHOU Zhu-qing, LAN Sheng-yin, WANG Wei-Jin, ZHU Xu-tong, XU Zhen-xiu and YANG Ze-minHuazhong Agricultural University, Wuhan 430070, P. R. China
