megaspore

American  

[meg-uh-spawr, -spohr] / ˈmɛg əˌspɔr, -ˌspoʊr /

noun

Botany.

1. the larger of the two kinds of spores characteristically produced by seed plants and a few fern allies, developing into a female gametophyte.

2. the embryo sac of a flowering plant.

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megaspore British  

/ ˈmɛɡəˌspɔː /

noun

1. Also called: macrospore.  the larger of the two types of spore produced by some spore-bearing plants, which develops into the female gametophyte Compare microspore

2. the cell in flowering plants that gives rise to the embryo sac

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megaspore Scientific  

/ mĕg′ə-spôr /

1. One of the two types of haploid spores produced by a heterosporous plant. Megaspores develop into female gametophytes and are usually larger than microspores.

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Other Word Forms

• megasporic adjective

Etymology

Origin of megaspore

First recorded in 1885–90; mega- + spore

Example Sentences

During the second phase, megagametogenesis, the surviving haploid megaspore undergoes mitosis to produce an eight-nucleate, seven-cell female gametophyte, also known as the megagametophyte or embryo sac.

From Textbooks • Jan. 1, 2015

The megaspore mother cell divides by meiosis to produce four haploid megaspores.

From Textbooks • Jan. 1, 2015

The megaspore divides three times to form an eight-cell stage.

From Textbooks • Jan. 1, 2015

The female gametophyte is formed from mitotic divisions of the megaspore, forming an eight-nuclei ovule sac.

From Textbooks • Jan. 1, 2015

The megaspore 763 is filled with tissue as in typical Gymnosperms, and from some of the superficial cells 3 to 5 archegonia are developed, characterized by long multicellular necks.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" by Various