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 endo sperm from maize kernels of inbred lines, their reciprocal hybrids, an d in some cases, F-2 and F-3 endosperm tissue were evaluated using flo w cytometry. Data relative to DNA endoreduplication patterns, percenta ge of nuclei undergoing endoreduplication, and mean DNA content per nu cleus were obtained. The patterns of endoreduplication and extent of D NA amplification differ among some inbreds. In all experiments, the en doreduplication patterns show that the F-1 endosperm is more similar t o the maternal parent than to the paternal parent. F-2 endosperms reve al little difference in endoreduplication patterns among individuals w ithin an F-2 family and no more variation than the F-1 endosperms. In contrast, F-3 endosperms showed greater variation among their endoredu plication patterns. These results indicate a maternal effect on endore duplication; that is, the genotype of the maternal parent's nuclear ge nome exerts control over the endoreduplication activities of endosperm tissue.