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In gymnosperms, the megagametophyte consists of several thousand cells and produces one to several archegonia, each with a single egg cell. The gametophyte becomes a food storage tissue in the seed. [27] In angiosperms, the megagametophyte is reduced to only a few cells, and is sometimes called the embryo sac. A typical embryo sac contains ...
The three cells left at the end of the cell near the micropylar become the egg apparatus with an egg cell in the center and two synergids. A cell wall forms around the other set of nuclei and forms the antipodals. The cells in the center develop into the central cell. This entire structure with its eight nuclei is called the embryonic sac.
Each male gametophyte typically consists of two to four cells enclosed within the protective wall of a pollen grain. The sporophyte of a flowering plant is often described using sexual terms (e.g. "female" or "male") based on the sexuality of the gametophyte it gives rise to. For example, a sporophyte that produces spores that give rise only to ...
This initially results in four single-celled haploid spores, each containing n unpaired chromosomes. [17] The single-celled haploid spore germinates, dividing by the normal process (mitosis), which maintains the number of chromosomes at n. The result is a multi-cellular haploid organism, called the gametophyte (because it produces gametes at ...
At least one of the spores develop into haploid female gametophytes, the megagametophytes. [1] The megaspore mother cell arises within the megasporangium tissue. In flowering plants the megasporangium is also called the nucellus, and the female gametophyte is sometimes called the embryo sac or embryonic sac.
The gametophyte is the multicellular structure (plant) that is haploid, containing a single set of chromosomes in each cell. The gametophyte produces male or female gametes (or both), by a process of cell division, called mitosis. In vascular plants with separate gametophytes, female gametophytes are known as mega gametophytes (mega=large, they ...
The gametophyte produces an egg cell. After fertilization, the ovule develops into a seed containing the embryo. [14] In flowering plants, the female gametophyte (sometimes referred to as the embryo sac) has been reduced to just eight cells inside the ovule. The gametophyte cell closest to the micropyle opening of the ovule develops into the ...
These microspore mother cells, also called microsporocytes, then undergo meiosis and become four microspore haploid cells. These new microspore cells then undergo mitosis and form a tube cell and a generative cell. The generative cell then undergoes mitosis one more time to form two male gametes, also called sperm.