megagametophyte
Quick Summary
The megagametophyte is the female gametophyte produced by a megaspore. It is a stage in the life cycle of plants, specifically in heterosporous plants like seed plants (gymnosperms and angiosperms). This haploid, multicellular stage develops from spores and gives rise to the female gametes, or eggs. In angiosperms, the megagametophyte, also known as the embryo sac, typically contains eight nuclei and is nourished by the parent sporophyte. After fertilization, the ovule containing the megagametophyte develops into a seed. The megagametophyte plays a crucial role in plant reproduction by producing the egg cell that, upon fertilization, forms the zygote and eventually the embryo.123456
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angiospermGeneral features) An eight-celled megagametophyte called the embryo sac produces the egg. (The prefix mega- denotes gametophytes emanating from female reproductive organs.)
Read More) An eight-celled megagametophyte called the embryo sac produces the egg. (The prefix mega- denotes gametophytes emanating from female reproductive organs.)
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The resulting megagametophyte produces the female gametes (eggs). This development (called megagametogenesis) involves free-nuclear mitotic divisions. The cell wall remains intact while the nucleus divides until the megagametophyte, or embryo sac, is formed. The embryo sac typically has eight nuclei. Free-nuclear mitotic division is also found in…
Read MoreThe resulting megagametophyte produces the female gametes (eggs). This development (called megagametogenesis) involves free-nuclear mitotic divisions. The cell wall remains intact while the nucleus divides until the megagametophyte, or embryo sac, is formed. The embryo sac typically has eight nuclei. Free-nuclear mitotic division is also found in…
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gnetophyteReproductive structures and function…begin to form, converting the megagametophyte (or female gametophyte) into a cellular structure. At the upper end, egg-bearing protective structures called archegonia are formed, each of which contains a haploid egg cell.
Read More…begin to form, converting the megagametophyte (or female gametophyte) into a cellular structure. At the upper end, egg-bearing protective structures called archegonia are formed, each of which contains a haploid egg cell.
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lycophyteLife cycle…of the female gametophyte, or megagametophyte, also may begin while the megaspore is still within the megasporangium. Free nuclear divisions (without wall formation) occur for a time, but ultimately walls appear and the megagametophyte ruptures the megaspore wall. These final stages in development usually occur on the soil after the…
Read More…of the female gametophyte, or megagametophyte, also may begin while the megaspore is still within the megasporangium. Free nuclear divisions (without wall formation) occur for a time, but ultimately walls appear and the megagametophyte ruptures the megaspore wall. These final stages in development usually occur on the soil after the…
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