centralcellen

Centralcellen, or the central cell, is a cell within the embryo sac of flowering plants (angiosperms). It lies at the center of the mature female gametophyte and contains two polar nuclei that arise from the meiotic products of the megagametophyte and subsequent mitotic divisions. In many species these polar nuclei may fuse before fertilization to form a diploid nucleus, while in others they remain separate until fertilization.

During fertilization, a pollen tube delivers two sperm cells. One sperm fuses with the egg cell to form the zygote, while a second sperm fuses with the central cell, producing a triploid endosperm nucleus. This endosperm nucleus divides to form the endosperm, a nutritive tissue that supports embryo development within the seed. Thus centralcellen is essential for seed formation and viability in most angiosperms.

Anatomically, the central cell is larger than the egg cell and is part of the typical seven- to eight-nucleate embryo sac, though its size and exact arrangement can vary among species. The central cell’s contribution to double fertilization links fertilization to the formation of nourishing endosperm, a key feature distinguishing angiosperms from other plant groups.

Variations exist in the details of polar-nucleus behavior and endosperm development across species, but the central cell's role in initiating endosperm formation remains a central component of flowering plant reproduction and seed biology.