gametophyte

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Related to gametophytic: sporophyte

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.
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; 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.
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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 ?
The aim of this work is the study of the gametophytic phase of D.
The descriptions of the gametophytic characters and sexual branches, as well as the habitat descriptions, illustrations and SEM photographs are based on Iberian specimens.
More specifically, this invention relates to the control of transgene transmission by male and/or female gametes or gametophytes using a gametophytic sterility trait.
During the gametophytic stage, additional spores may be produced asexually.
The first, obtaining the small plants, is performed in greenhouses during the summer, and consists of growing the microscopic gametophytic phase from the motile sperms attached to appropriate collectors (plastic filaments placed on frames).
Observed patterns may be explained by a combination of increased outcrossing derived from the greater relative importance of small bees and butterflies as pollinators, and increased gametophytic competition resulting from increased overall visitation rates to individual flowers during the MD pollination regime.
The morphology of both gametophytic and sporophytic generations is an upright frond with many branched, flattened, corticated blades supported by a narrow stipe (Algal Morphology Group Four sensu Steneck and Dethier 1994) that arises from a perennial basal disc holdfast.
This "mentor effect": can yield selfing rates as high as 32% in experimental crosses in Helianthus (Desrochers and Rieseberg, in press), and it appears to be a relatively common phenomenon in experimental crosses between plant species with either gametophytic or sporophytic SI systems (Pandey 1979; reviewed in Richards 1986).
Screening of cotton genotypes for heat tolerance via in vitro gametophytic selection technique.
Identification of a Skp1-like protein interacting with SFB, the pollen S determinant of the gametophytic self-incompatibility in Prunus.
S-RNase uptake by compatible pollen tubes in gametophytic self-incompatibility.