Reproduction of Gymnosperms

May 13, 2024 | by Bloom Code Studio

All gymnosperms are heterosporous and produce microspores and megaspores.
Microspores are produced in the pollen cone and become pollen grains, and megaspores produce in archegonia are present in ovulating cones.
Some species have both male and female cones in the same plants (e.g. Pinus), while male and female cones are found in different plants seen in other plants (e.g. Cycas).
Male cones: male cones bear microsporophylls, which have the microsporangia that form the microspores i.e. haploid. From these microspores, male gamete developed known as pollen grains, and some microspores degenerate.
Female cones: female cones have megasporophylls, that bear the ovules containing the megasporangium, which produce the haploid megaspores and a mother megaspore.
A mother megaspore undergoes meiotic division to produce four megaspores; from these megaspores, one becomes mature and develops into a multicellular female gametophyte.
Female cones are larger than male cones.
For pollination, male and female gametes must be in contact with each other; this type of union occurs by wind and animal or insect.
When pollen grains and female ovules are in contact with each other, fertilization of gymnosperms occurs.
After fertilization zygote is formed within the gymnosperm seed and develops a new sporophyte.

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