megaspore


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Related to megaspore: megagametophyte, generative cell

mac·ro·spore

(mak'rō-spōr),
The larger of two spore types of certain protozoans or fungi.
Synonym(s): megalospore, megaspore
[macro- + G. sporos, seed]

megaspore

or

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.
References in periodicals archive ?
(2009) found that exposure to 50 mg [L.sup.-1] cadmium led to a significant reduction in megaspore germination, which was as low as 58%.
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.
megasporangium The structure in which megaspores are produced.
Elapsed time from megaspore stage to somatically mature female gametophyte (Table 1) is approximately 150 days in Ginkgo (Favre-Duchartre 1958) and ranges from 120 days (Zamia; D.
The nucellus beneath the megaspore mother cells continuously elongated and developed into mature finger- like shape (Fig.
Experimental studies on megaspore viability, parthenogenesis and sporophyte formation in Marsilea, Pilularia and Regnellidium.
The primary sporogenous cell enlarges to form the megasporocyte (megaspore mother cell-MMC) (Fig.
megaspore: Haploid cell produced by meiosis in the ovules of angiosperms; a single megasporocyte produces four megaspores, only one of which remains functional.
Abbreviations: MMC, megaspore mother cell; PMC, pollen mother cell.
In this primordium, an archeosporial cell produces a megaspore mother cell, which undergoes meiosis, forming a linear tetrad.