Spore biology3/13/2023 Urediniospores: spores produced by a uredinium in some fungi such as rusts or smuts.Aeciospores: spores produced by an aecium in some fungi such as rusts or smuts.Basidiospores: spores produced by a basidium, characteristic of basidiomycetes.Ascospores: spores produced by an ascus, characteristic of ascomycetes.Zygospores: spores produced by a zygosporangium, characteristic of zygomycetes.Sporangiospores: spores produced by a sporangium in many fungi such as zygomycetes.Since fungi are often classified according to their spore-producing structures, these spores are often characteristic of a particular taxon of the fungi. In fungi and fungus-like organisms, spores are often classified by the structure in which meiosis and spore production occurs. In contrast, in many seed plants and heterosporous ferns, only a single product of meiosis will become a megaspore (macrospore), with the rest degenerating. Spores can be classified in several ways: Diploid cells undergo meiosis to produce haploid spores. ![]() Among sporogenic dikaryotic cells, karyogamy (the fusion of the two haploid nuclei) occurs to produce a diploid cell. Dikaryotic cells result from the fusion of two haploid gamete cells. Spores are usually haploid and grow into mature haploid individuals through mitotic division of cells ( Urediniospores and Teliospores among rusts are dikaryotic). In flowering plants, these sporangia occur within the carpel and anthers, respectively.įungi commonly produce spores during sexual and asexual reproduction. Such plants typically give rise to the two kind of spores from within separate sporangia, either a megasporangium that produces megaspores or a microsporangium that produces microspores. Heterosporous plants, such as seed plants, spikemosses, quillworts, and ferns of the order Salviniales produce spores of two different sizes: the larger spore (megaspore) in effect functioning as a "female" spore and the smaller (microspore) functioning as a "male". Plants that are homosporous produce spores of the same size and type. Vascular plants are either homosporous (or isosporous) or heterosporous. Vascular plant spores are always haploid. ![]() Spores germinate to give rise to haploid gametophytes, while seeds germinate to give rise to diploid sporophytes.Ĭlassification of spore-producing organisms The main difference between spores and seeds as dispersal units is that spores are unicellular, the first cell of a gametophyte, while seeds contain within them a developing embryo (the multicellular sporophyte of the next generation), produced by the fusion of the male gamete of the pollen tube with the female gamete formed by the megagametophyte within the ovule. In common parlance, the difference between a "spore" and a " gamete" is that a spore will germinate and develop into a sporeling, while a gamete needs to combine with another gamete to form a zygote before developing further. The term spore derives from the ancient Greek word σπορά spora, meaning " seed, sowing", related to σπόρος sporos, "sowing", and σπείρειν speirein, "to sow".
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