megaspore

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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.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

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.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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"
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Structural studies on Lower Gondwana megaspores. Part II: Specimens from Brazil and Mhukuru coalfield, Tanganyika.
The reproductive structures consist of microspores and megaspores contained within sporocarps (Mahlberg and Baldwin, 1975).
Megasporogenesis in heterosporous fern: features of the organelles in meiotic cells and young megaspores. J.
Sporogenesis usually excludes discussion of megasporogenesis in the seed plants where resultant megaspores remain enclosed within surrounding tissues of the megasporangium (ovule) and, at least in angiosperms, lack an elaborate sporoderm.
The spores produced in the ovules are larger than the spores produced in the anthers and are therefore termed megaspores. Likewise the egg (in the ovule) is larger, a megagamete.
One reason might be that the fossil records of freshwater macrophytes are often based on fruit, seeds, and megaspores. However, much of the reproduction is asexual and vegetative parts usually lack cuticle and decay readily, so they are unlikely preserved as fossils (Collinson, 1988).
(1980): Stratigraphy and palaeogeography of the Lower Triassic in Poland on the basis of megaspores. Acta Geologica Polonica, 30: 417-470.
megasporangium The structure in which megaspores are produced.
In both phenomena, the diploid chromosome complement is first restored and then the diploid complement undergoes mitotic (equational) division resulting in unreduced gametes (microspores during male meiosis and megaspores during female meiosis).
The aim of this study was to investigate germination of megaspores and initial development of sporophytes of Regnellidium diphyllum in the presence of nickel, providing information on the influence of this metal in the establishment and growth of the species.