Maternal effects influencing DNA endoreduplication in developing endosperm of Zea mays

A large proportion of the nuclei in developing endosperm of Zea mays L. undergoes endoreduplication. Nuclear preparations of the entire endosperm from maize kernels of inbred lines, their reciprocal hybrids, and in some cases, F-2 and F-3 endosperm tissue were evaluated using flow cytometry. Data relative to DNA endoreduplication patterns, percentage of nuclei undergoing endoreduplication, and mean DNA content per nucleus were obtained. The patterns of endoreduplication and extent of DNA amplification differ among some inbreds. In all experiments, the endoreduplication patterns show that the F-1 endosperm is more similar to the maternal parent than to the paternal parent. F-2 endosperms reveal little difference in endoreduplication patterns among individuals within an F-2 family and no more variation than the F-1 endosperms. In contrast, F-3 endosperms showed greater variation among their endoreduplication patterns. These results indicate a maternal effect on endoreduplication; that is, the genotype of the maternal parent's nuclear genome exerts control over the endoreduplication activities of endosperm tissue.