megaspore

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mac·ro·spore

(mak'rō-spōr),

The larger of two spore types of certain protozoans or fungi.

[macro- + G. sporos, seed]

megaspore

macrospore

the larger of two types of SPORES produced by many ferns and seed plants. The megaspore gives rise to a female GAMETOPHYTE in ferns and in seed plants, and in flowering plants becomes the EMBRYO SAC. Compare MICROSPORE.

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References in periodicals archive ?

The functional megaspore undergoes three successive mitoses resulting in the formation of an 8- nucleate embryo sac of the Polygonum type.

Microsporogenesis, Megasporogensis and Male and Female Gametophyte Development in Feijoa sellowiana (Myrtaceae)

Megaspores were considered to have germinated when an apical globular green structure with a crown of rhizoids was observed (Wunder et al., 2009).

Lead tolerance and accumulation in initial sporophytes of Regnellidium diphyllum Lindm

This single haploid megaspore undergoes three consecutive mitotic divisions to produce two, then four, and finally eight haploid nuclei within a single cell in the ovule.

Chapter 12: Sexual reproduction and inheritance

megaspore A haploid spore (N) that will develop into a female gametophyte.

Glossary

Twenty-five megaspores were placed in each glass vial (4.5 x 10 cm) with 25 mL of the culture medium, with four repetitions for each treatment.

Effects of nickel on the fern Regnellidium diphyllum Lindm

Sporangium wall pigmented with brown; megaspores with short ridges, wart-like projections (tuberculate to papillate) or almost smooth; plant terrestrial or amphibious in wet clay soils or on rock outcrops.

PTERIDOPHYTES OF NORTHEAST ALABAMA AND ADJACENT HIGHLANDS

However, not all seed-fertile triploid Musa accessions generate a high frequency of 2n megaspores (Ortiz, 1995).

Segregation at microsatellite loci in haploid and diploid gametes of Musa

The inner integument initiates first, and then the outer integument develops into a small protuberance at the megaspore mother cell stage.

Developmental and Cytochemical Features of Female Gametophyte in Endemic Lathyrus undulatus (Fabaceae)

Twenty five megaspores were placed in each glass vial (4.5 x 10 cm) with 25 mL of the solution and there were six repetitions for each treatment.

Effects of 2,4-D on the germination of megaspores and initial development of Regnellidium diphyllum Lindman (Monilophyta, Marsileaceae)/Efeitos do 2,4-D sobre a germinacao de megasporos e o desenvolvimento inicial de Regnellidium diphyllum Lindman (Monilophyta, Marsileaceae)

megasporocyte: Megaspore mother cell; this diploid cell undergoes meiosis to produce four haploid megaspores in the ovules of angiosperms.

Glossary

and ultrastructure of megaspores and microspores of Isoetes savatieri

Microspore morphology of Isoetes species (Lycophyta) from southern South America

However, in most ovules, shortly after megasporogenesis from one to seven nucellar cells in the area adjacent to the functional megaspore enlarged and their nuclei became prominent.

Apomixis and sexuality in some Paspalum species

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