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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.
There is debate as to whether endospory or heterospory evolved first. Some debate centers upon the requirement of endospory to develop before heterospory. [2] Endospory is assumed to follow heterospory but it has been suggested that without endospory, early plant species dependency on water fertilization and environmental impacts on gametophytic gene expression would have reduced the chances ...
The exosporium is the outer surface layer of mature spores.In plant spores it is also referred to as the exine.Some bacteria also produce endospores with an exosporium, of which the most commonly studied are Bacillus species, particularly Bacillus cereus and the anthrax-causing bacterium Bacillus anthracis.
B. subtilis can divide symmetrically to make two daughter cells (binary fission), or asymmetrically, producing a single endospore that is resistant to environmental factors such as heat, desiccation, radiation and chemical insult which can persist in the environment for long periods of time. The endospore is formed at times of nutritional ...
Once mature, this single celled gametophyte is 90% smaller than the female gametophytes in other gymnosperm orders. [14] After fertilization, the remaining female gametophyte tissue in gymnosperms serves as the nutrient source for the developing zygote (even in Gnetophyta where the diploid zygote cell is much smaller at that stage, and for a ...
Spores are usually haploid and grow into mature haploid individuals through mitotic division of cells (Urediniospores and Teliospores among rusts are dikaryotic). Dikaryotic cells result from the fusion of two haploid gamete cells. Among sporogenic dikaryotic cells, karyogamy (the fusion of the two haploid nuclei) occurs to produce a diploid cell.
Except in the case of some submerged aquatic plants, the mature pollen grain has a double wall. The vegetative and generative cells are surrounded by a thin delicate wall of unaltered cellulose called the endospore or intine, and a tough resistant outer cuticularized wall composed largely of sporopollenin called the exospore or exine. The exine ...
A stained preparation of Bacillus subtilis showing endospores as green and the vegetative cell as red. The Schaeffer–Fulton stain is a technique designed to isolate endospores by staining any present endospores green, and any other bacterial bodies red. [1]