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Spores form a part of the life cycles of a diverse range of organisms such as many bacteria, plants, algae, fungi and some protozoa. In Saccharomyces cerevisiae (Kingdom Fungi), the set of early genes activating sporulation is induced by Ime1 (Inducer of Meiosis 1) and a regulator of middle genes is Ndt80p. [4]
Plant spores are most obvious in the reproduction of ferns and mosses. However, they also exist in flowering plants where they develop hidden inside the flower. For example, the pollen grains of flowering plants develop out of microspores produced in the anthers. Reproductive spores grow into multicellular haploid individuals or sporelings.
An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Bacillota. [1] [2] The name "endospore" is suggestive of a spore or seed-like form (endo means 'within'), but it is not a true spore (i.e., not an offspring). It is a stripped-down, dormant form to which the bacterium can reduce itself.
Flowering plants contain microsporangia in the anthers of stamens (typically four microsporangia per anther) and megasporangia inside ovules inside ovaries. In all seed plants, spores are produced by meiosis and develop into gametophytes while still inside the sporangium. The microspores become microgametophytes (pollen).
Spores form part of the life cycles of many plants, algae, fungi and protozoa. [2] They were thought to have appeared as early as the mid-late Ordovician period as an adaptation of early land plants. [3] Bacterial spores are not part of a sexual cycle, but are resistant structures used for survival under unfavourable conditions. [4]
Mucor spores or sporangiospores can be simple or branched and form apical, globular sporangia that are supported and elevated by a column-shaped columella. Mucor species can be differentiated from molds of the genera Absidia , Rhizomucor , and Rhizopus by the shape and insertion of the columella, and the lack of stolons and rhizoids .
A 2009 study compared the density of spores found in soil (about 10 6 spores per gram) to that found in human feces (about 10 4 spores per gram). The number of spores found in the human gut was too high to be attributed solely to consumption through food contamination. [15] In some bee habitats, B. subtilis appears in the gut flora of honey ...
A zoosporangium is the asexual structure in which the zoospores develop in plants, fungi, or protists (such as the Oomycota). Developing sporangia of oomycetes go through a process of cleavage in which a protein kinase , in the case of Phytophthora infestans , induces the sporangial cytoplasm to split and release the various zoospores. [ 4 ]