Sporogenesis is the production of in biology. The term is also used to refer to the process of reproduction via spores. Reproductive spores were found to be formed in eukaryotic organisms, such as plantsalgae and fungiduring their normal reproductive life cycle.
Dormant spores are formed, for example by certain fungi and algae, primarily in response to unfavorable growing conditions.
Most eukaryotic spores are haploid and form through cell division, though some types are diploid or dikaryons and form through cell fusion. Reproductive spores are generally the result of cell division, most commonly meiosis e. Sporic meiosis is needed to complete the sexual life cycle of the organisms using it. In some cases, sporogenesis occurs via mitosis e. Mitotic sporogenesis is a form of asexual reproduction.
Examples are the conidial fungi Aspergillus and Penicilliumfor which mitospore formation appears to be the primary mode of reproduction. Other Sporogenesis asexual reproduction, such as ascomycetesutilize both mitotic and meiotic spores. The red alga Polysiphonia alternates between mitotic and meiotic sporogenesis and both processes are required to complete its complex reproductive life cycle. In the case of dormant spores in eukaryotes, sporogenesis often occurs as a result of fertilization or karyogamy forming a diploid spore equivalent to a zygote.
Therefore, zygospores are the result of sexual reproduction. Reproduction via spores involves the spreading of the spores by water or air.
Algae and some fungi chytrids often use motile zoospores that can swim to new locations before developing into sessile organisms.
Airborne spores Sporogenesis asexual reproduction obvious in fungi, for example when they are released from puffballs. Other fungi have more active spore dispersal mechanisms. For example, the fungus Pilobolus can shoot its sporangia towards light.
Plant spores designed for dispersal are also referred to as diaspores. 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. In heterosporous organisms, two types of spores exist: In homosporous organisms, all spores look alike and grow into individuals carrying reproductive parts of both genders. Sporogenesis occurs in reproductive structures termed sporangia.
The process involves sporogenous cells sporocytes, also called spore mother cells undergoing cell division to give rise to spores.
In meiotic sporogenesis, a diploid spore mother cell within the sporangium undergoes meiosis, producing a tetrad of haploid spores. In organisms that are heterosporoustwo Sporogenesis asexual reproduction of spores occur: Microsporangia produce male microspores, and megasporangia produce female megaspores. In megasporogenesis, often three of the four spores degenerate after meiosis, whereas in microsporogenesis all four microspores survive.