Nevertheless, said the biologists, the fungus Gibberella zeae outguns the previous record holder, the fungus Pilobolus, by almost a hundred-fold. It also outperforms a rifle, which launches its bullet with less than one-tenth that acceleration.
The researchers -- Frances Trail and Iffa Gaffoor of Michigan State University, and Steven Vogel of Duke University -- published their findings in the June 2005 issue of Fungal Genetics and Biology. The study was supported by the U.S. Department of Agriculture and the Michigan Agricultural Experiment Station.
According to Vogel, the "bioballistics" of the fungus offers a dramatic lesson in the physics of scaling. At the infinitesimal scale of the fungus' spore, atmospheric drag plays an enormous role -- hence the need for an extremely high ejection speed to achieve even the most modest dispersal of its spore.
"To get a literal feel for a world in which drag makes more impact than does gravity, just inflate a six-inch balloon and throw it as hard as you can," said Vogel.
The purpose of the study that revealed the fungus's extraordinary launch capabilities was to better understand the biological mechanism behind the fungal supergun. Basically, the gun is powered by the buildup of pressure inside the spore-containing fungal fruiting body, called the perithecium, due to the ability of sap to create an osmotic pressure. Such pressure is due to water flowing across a membrane into the perithecium as it tries to equalize the concentration of a salt solution inside the chamber. In the case of the fungus, at question was whether the suga
Contact: Dennis Meredith