gametophyte


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

gametophyte

(gəmē`təfīt'), phase of plant life cycles in which the gametes, i.e., egg and sperm, are produced. The gametophyte is haploid, that is, each cell contains a single complete set of chromosomes, and arises from the germination of a haploid spore. In many lower plants, the gametophyte phase is the dominant plant form; for example, the familiar mosses are the gametophyte form of the plants. The alternate phase of the plant life cycle is the sporophyte, the diploid plant form, with each cell containing two complete sets of chromosomes. For example, in mosses the sporophyte is a capsule atop a slender stalk that grows out of the top of the gametophyte. The sporophyte develops from the union of two gametes, such as an egg fertilized by a sperm; in turn, the sporophyte forms spores that develop into gametophytes. The alternation between haploid gametophyte and diploid sporophyte phases, known as alternation of generations, occurs in all multicellular plants. As plants advanced in evolutionary development, the sporophyte became the increasingly dominant plant form and the gametophyte form has been correspondingly reduced. In contrast to mosses, for example, in the advanced angiosperms the male and female gametophytes are reduced to three-celled and seven-celled structures, respectively, found within the reproductive organs of the familiar flowering plant (the sporophyte). See also fertilizationfertilization,
in biology, process in the reproduction of both plants and animals, involving the union of two unlike sex cells (gametes), the sperm and the ovum, followed by the joining of their nuclei.
..... Click the link for more information.
; reproductionreproduction,
capacity of all living systems to give rise to new systems similar to themselves. The term reproduction may refer to this power of self-duplication of a single cell or a multicellular animal or plant organism.
..... Click the link for more information.
.

Gametophyte

 

sexual generation in those plants that exhibit alternation of generations. The gametophyte alternates in the development cycle with the asexual generation or sporophyte. In many plants the gametophyte carries on an autonomous existence, independent of the sporophyte. In some cases it is not distinguishable from the sporophyte by its external appearance (for example, the gametophyte in many algae); in others it is very distinct, for example, in the prothallia of ferns, horsetails, and lycopodia. In angiospermous plants the gametophyte is reduced to a pollen grain (male gametophyte) and to an embryo sac (female gametophyte). The gametophyte cell nuclei are characterized by half the number (haploid) of chromosomes in comparison to the cell nuclei of the sporophyte.

gametophyte

[gə′mēd·ə‚fīt]
(botany)
The haploid generation producing gametes in plants exhibiting metagenesis.
An individual plant of this generation.
References in periodicals archive ?
Their pinnate dorsiventral form and their development resembles the gametophyte organization.
Plant not filamentous, occurring as both gametophyte and sporophyte (gametophytes usually in association with sporophytes).
A contribution to the gametophyte morphology and development in several species of Thelypteris, Thelypteridaceae.
A histological comparison of the development of pollen and female gametophytes in fertile and sterile Cryptomeria japonica.
stellatus [kappa] - [iota] ([mu]/[nu]) T: tetrasporophyte; FG: female gametophyte; G: gametophyte; NF: nonfructified thalli; TB: tetrasporopblastic thalli; H: heterosporic thalli: ([female] cistocarpic branch; [direct sum] tetrasporic branch); (1) yields (maximum value found) expressed as a percentage of dry weight [+ or -] standard error; (3) composition determined by [sup.1]H-NMR; (4) composition determined by FTIR-ATR and FT-Raman analysis of ground seaweed samples; the carrageenans are identified according to the Greek lettering system and letter code (2) proposed by Knutsen et al.
Gametophyte development and conservation of Ctenitis submarginalis (Dryopteridaceae) in Buenos Aires Province, Argentina.
The role of spore germination and gametophyte development in habitat selection: temperature responses in certain temperate and tropical ferns.
In Arabidopsis thaliana six genes encoding these proteins were found; their physiological functions are not fully known [16], but it seems to require for male gametophyte development maturation of the pollen and its germination.
For example, in her performance at the 2010 Grammy Awards, Lady Gaga wore a heart-shaped Armani Prive' costume with giant shoulders that looked, to Pryer's trained eyes, exactly like the bisexual reproductive stage of the ferns, called a gametophyte.
The male gametophyte equals the mature pollen grain that arises in the anther and consists of only three cells (i.e., two sperm cells and a vegetative cell).