by Danielle Dusold

Created on: December 04, 2008

The Fungi Kingdom presents a variety of spore types that utilize mechanisms that are not seen in any other group of organisms. Chytridiomycoda, Blastiocladiomycota, Neocallimastigomycota, Ascomycota, Zygomycota, Glomeromycota, and Basidiomycota make up the major phyla of fungi. Sexual and asexual spores of these fungi are dispersed into the environment by varying mechanisms, from forcibly dispersing spores to attracting other organisms to do the fungi's dirty work of spore dispersal. Spores are released from the sporophore by an active or passive release.

There are two types of spore release: ballistospore release and spore discharge. Ballistospore release is essentially a "gunshot" maneuver. The basidia houses the development of basidiospores, a reproductive spore that is discharged from the sterigmata by a forcible mechanism. Hence, the name "ballistospore", like ballistics. The force is driven by a change in the center of gravity of the spore. A droplet of fluid called the Buller's drop accumulates at the tip of the basidiospore, created by the sugars in the cell wall attracting water vapor from the surrounding air during maturation. The Buller's drop develops into a water droplet at the hilum (the tip of the spore) and while this is occurring, condensation is also occurring on the adaxial side of the basidiospore. Once these water droplets combine, the center of mass and the surface tension rapidly change, which leads to the release of the basidiospore.

Spore discharge is common in Ascomycetes. When a cell becomes turgid, a spore is released from it due to the hydrostatic pressure building up inside of the cell. At the hymenium or ostiole, asci emerge at the tip of the ascus and are ejected over some distance. In the case of fungi such as Pilobolus (a dung fungi), the sporangiophore forms a sporangium that has a gooey interior. The gooey interior begins to dry, which causes the tension to increase. Over time the gel will crack and the sporangium is released into the atmosphere. Both the ascophores and sporangiophores are aimed towards sunlight to increase their likelihood of jumping over the big guys (i.e. plants and trees) and finding a new home to grow up and repeat the process upon.

Passive spore release either occurs in a dry condition or a mucilage, which is a polymer produced by the fungi that helps store water and spores. This is commonly seen in a giant puffball mushroom. When the puffball cracks open, it allows the wind to carry away the spores. Another

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