- epigenetic programming in the zygotic pronuclei
The global programming of epigenetic modifications in the zygote following fertilization. The paternal genome undergoes active DNA demethylation before the first cell division, while the adjacent maternal genome is protected from this process.
- zygote elongation
The process in which the zygote irreversibly increases in size in one dimension after fertilization. An example of such a process is found in Arabidopsis thaliana.
- epigenetic programing of male pronucleus
The global programming of epigenetic modifications in the male pronucleus of the newly fertilized zygote. The most major change in the paternal genome is DNA demethylation, which takes place before the first cell division.
- zygotic genome activation
A process that contributes to the onset of de novo transcription from the zygotic genome as part of the maternal-to-zygote transition in gene expression. The zygote overcomes the silencing that has been established. The cause of this silencing could be due to several factors: chromatin modifications leading to repression, or lack of adequate transcription machinery.
- double fertilization forming two zygotes
Rudimentary double fertilization where one of the two sperm nuclei from the pollen tube fuses with the egg nucleus to form a 2n zygote, and the other fuses with the ventral canal cell nucleus to form a second zygote, which soon degenerates. An example of this process is found in the Gnetophytes, such as Welwitschia mirabilis.
- double fertilization forming a zygote and endosperm
Fertilization where one of the two sperm nuclei from the pollen tube fuses with the egg nucleus to form a 2n zygote, and the other fuses with the two polar nuclei to form the 3n primary endosperm nucleus and then develops into the endosperm. The ploidy level of the 2n zygote and 3n primary endosperm nucleus is determined by the ploidy level of the parents involved. An example of this component is found in Arabidopsis thaliana.
- zygote asymmetric cytokinesis in embryo sac
The division of the zygote in a plane perpendicular to the long axis of the embryo sac to produce a larger basal cell near the micropyle and a small terminal cell close to what was the central cell and is now the developing endosperm. An example of this process is found in Arabidopsis thaliana.