Search results
Results From The WOW.Com Content Network
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 pollen then produces ...
The female gamete is produced inside the embryo sac of the ovule. In angiosperms the division of a generative cell into two, sperm nuclei, resulting in the production male gametes (always two), which develop inside the pollen grain (in 30% of species) or the pollen tube (in 70% of species), respectively, of the plant.
Flowering plants contain non-motile sperm inside pollen, while some more basal plants like ferns and some gymnosperms have motile sperm. [2] Sperm cells form during the process known as spermatogenesis, which in amniotes (reptiles and mammals) takes place in the seminiferous tubules of the testicles. [3]
As in animals, female and male gametes are called, respectively, eggs and sperm. In extant land plants, either the sporophyte or the gametophyte may be reduced (heteromorphic). [2] No extant gametophytes have stomata, but they have been found on fossil species like the early Devonian Aglaophyton from the Rhynie chert. [3]
An antheridium is a haploid structure or organ producing and containing male gametes (called antherozoids or sperm). The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. [1] The androecium is also the collective term for the stamens of flowering plants.
Pollen itself is not the male gamete. [4] It is a gametophyte, something that could be considered an entire organism, which then produces the male gamete.Each pollen grain contains vegetative (non-reproductive) cells (only a single cell in most flowering plants but several in other seed plants) and a generative (reproductive) cell.
Or, with bisexual and at least one of male and female flowers on the same plant. [2] Protandrous: (of dichogamous plants) having male parts of flowers developed before female parts, e.g. having flowers that function first as male and then change to female or producing pollen before the stigmas of the same plant are receptive. [6]
It is present in both plants and animals but is always extremely rare. [36] Trioecy occurs in about 3.6% of flowering plants. [37] Trioecy may infrequently be referred to as tridioecy. [38] Trimonoecy (also called androgynomonoecy) is when male, female, and hermaphrodite flowers are present on the same plant. [28] [39] Triomonoecy is rare. [40]