megaspore


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Related to megaspore: megagametophyte, generative cell

meg·a·spore

 (mĕg′ə-spôr′)
n.
A spore that gives rise to a female gametophyte and is larger than a microspore.

meg′a·spor′ic adj.

megaspore

(ˈmɛɡəˌspɔː)
n
1. (Botany) Also called: macrospore the larger of the two types of spore produced by some spore-bearing plants, which develops into the female gametophyte. Compare microspore1
2. (Botany) the cell in flowering plants that gives rise to the embryo sac
ˌmegaˈsporic adj

meg•a•spore

(ˈmɛg əˌspɔr, -ˌspoʊr)

n.
the larger of the two kinds of spores characteristically produced by seed plants and a few fern allies, developing into a female gametophyte. Compare microspore.
[1885–90]
meg`a•spor′ic (-ˈspɔr ɪk, -ˈspɒr-) adj.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.megaspore - larger of the two types of spore produced in heterosporous plantsmegaspore - larger of the two types of spore produced in heterosporous plants; develops in ovule into a female gametophyte
spore - a small usually single-celled asexual reproductive body produced by many nonflowering plants and fungi and some bacteria and protozoans and that are capable of developing into a new individual without sexual fusion; "a sexual spore is formed after the fusion of gametes"
References in periodicals archive ?
The megaspore tetrads are arranged linearly, and the megaspore at the chalazal end is functional.
Middle Triassic (Anisian) Megaspore from Western Salt Range, Pakistan.
For megaspore germination and sporophyte development Meyer's solution (Meyer et al.
Under field conditions early drought (occurring at green bud stage) could lead to a decrease in oil content of seeds implying that allocation of assimilates to the ovule at the early stage of the megaspore could be related to the final oil concentration (Wright et al.
Transcriptome analysis of the Arahidopsis megaspore mother cell uncovers the importance of RNA helicases for plant germline development.
Megaspore morphology in the Selaginellaceae in a phylogenetic context: A study of the megaspore surface and wall structure using scanning electron microscopy.
In the nucleus tissue, there is a single diploid megaspore mother cell that undergoes meiosis and cytokinesis to produce four haploid megaspores (see Figure 12-5).
Micromorphology of outer exospore coatings in Selaginella megaspore.
asexual reproduction by seeds) is a common trait in the genus, being apospory (in which a non reduced megagametophyte originates from a somatic cell, usually a nucellar cell) the most frequent type, and diplospory (in which a non reduced megaspore originates from the reproductive cell itself, with the later failing to successfully complete meiosis) only of occasional occurrence (Quarin, 1992).
Example: In pine trees, the immature male gametophyte is a megaspore, the embryonic pine seed, a pollen tube or a pollen grain?
The process of meiosis may be bypassed and the seed formed directly from a diploid megaspore.
These organisms are initiated from a haploid megaspore (formed by meiosis within the body of the diploid sporophyte) and enter a period of free nuclear development that may be extensive (all nonflowering seed plants) or quite limited (angiosperms).