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An endosperm is formed after the two sperm nuclei inside a pollen grain reach the interior of a female gametophyte or megagametophyte, also called the embryonic sac.One sperm nucleus fertilizes the egg cell, forming a zygote, while the other sperm nucleus usually fuses with the binucleate central cell, forming a primary endosperm cell (its nucleus is often called the triple fusion nucleus).
Authors may at times report the total combined ploidy of all nuclei present within the cell membrane of a syncytium, [37] though usually the ploidy of each nucleus is described individually. For example, a fungal dikaryon with two separate haploid nuclei is distinguished from a diploid cell in which the chromosomes share a nucleus and can be ...
In the most common type of megagametophyte development in flowering plants (the Polygonum type), three mitotic divisions are involved in producing the gametophyte, which has seven cells, one of which (the central cell) has two nuclei that later merge to make a diploid nucleus.
Each haploid nucleus then undergoes two rounds of mitosis which creates 4 haploid nuclei on each end of the embryonic sac. One nucleus from each set of 4 migrates to the center of the embryonic sac. These form the binucleate endosperm mother cell. This leaves three remaining nuclei on the micropylar end and three remaining nuclei on the ...
Location of ovules inside a Helleborus foetidus flower. In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the integument, forming its outer layer, the nucellus (or remnant of the megasporangium), and the female gametophyte (formed from a haploid megaspore) in its center.
The parts of a flower Double fertilization. Double fertilization or double fertilisation (see spelling differences) is a complex fertilization mechanism of angiosperms.This process involves the fusion of a female gametophyte or megagametophyte, also called the embryonic sac, with two male gametes (sperm).
A typical embryo sac contains seven cells and eight nuclei, one of which is the egg cell. Two nuclei fuse with a sperm nucleus to form the primary endospermic nucleus which develops to form triploid endosperm, which becomes the food storage tissue in the seed.
The resulting zygote develops into an embryo, while the triploid endosperm (one sperm cell plus two female cells) and female tissues of the ovule give rise to the surrounding tissues in the developing seed. The ovary, which produced the female gametophyte(s), then grows into a fruit, which surrounds the seed(s).