Ovule Abortion in Quercus (Fagaceae)

This study deals with the occurrence and relative abundance of four different types of abortive ovules in three species of Quercus. It was found that, contrary to previous literature, fertilization does not always occur in the abortive ovules. The most common type of abortive ovule is the one in which a normal embryo sac develops, yet fertilization does not occur. The absence of embryo sacs and the occurrence of empty embryo sacs account for abortion in other ovules. All types of abortive ovules can occur in the same ovary. It is proposed that all of the ovules that develop a normal embryo sac are potential seeds, but the first one to be fertilized suppresses the normal development of the others.