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There are two key differences between mammalian and plant gametogenesis. First, there is no predetermined germline in plants. Male or female gametophyte-producing cells diverge from the reproductive meristem, a totipotent clump of developing cells in the adult plant that creates all the flower's features (both sexual and asexual structures).
The male gametophyte is produced inside a pollen grain within the anther and is non-motile, but can be distributed by wind, water or animal vectors. When a pollen grain lands on a mature stigma of a flower it germinates to form a pollen tube that grows down the style into the ovary of the flower and then into the ovule.
The female gametophyte in gymnosperms differs from the male gametophyte as it spends its whole life cycle in one organ, the ovule located inside the megastrobilus or female cone. [14] Similar to the male gametophyte, the female gametophyte normally is fully dependent on the surrounding sporophytic tissue for nutrients and the two organisms ...
Megagametogenesis creates the female gametophyte, which is an integral part of pollination, a very prominent process in plants. The male counterpart to megagametogenesis is called microgametogenesis. Microgametogenesis is the process of the formation of the male gametophyte.
The smaller gamete is male, a sperm cell, whereas the larger gamete is female, typically an egg cell. Anisogamy is predominant among multicellular organisms. [1] In both plants and animals, gamete size difference is the fundamental difference between females and males. [2] Anisogamy most likely evolved from isogamy. [3]
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 ...
However, the parent sporophyte may be monoecious, producing both male and female gametophytes or dioecious, producing gametophytes of one gender only. Seed plant gametophytes are extremely reduced in size; the archegonium consists only of a small number of cells, and the entire male gametophyte may be represented by only two cells. [27]
Male and female gametocytes are the components of the malaria parasite life cycle which are taken up from an infected host bloodstream by mosquitoes and thus mediate disease transmission. These gamete precursors are quite distinct from their asexual blood stage counterparts and this is reflected in their distinct patterns of gene expression ...