MONEY, N. P.*; PRINGLE, A.; PATEK, S. N.; FISCHER, M.; STOLZE, J.; Miami University; Harvard; University of California, Berkeley; College of Mount St. Joseph, Cincinnati; Miami University: Rapid Discharge of Mushroom Spores

Ballistospore discharge is a feature of 30,000 species of mushrooms, basidiomycete yeasts, and pathogenic rusts and smuts. A few seconds prior to the launch of a ballistospore, a drop of fluid (called Buller�s drop) develops at its base. This drop enlarges until it approaches the volume of the spore and then, �instantaneously,� spore and drop are catapulted into the air. Until recently, the launch process eluded analysis, but spore motion has now been captured using ultra high speed video microscopy. Images obtained at camera speeds of up to 100,000 frames per second demonstrate that spore discharge occurs when the expanding Buller�s drop merges with fluid on the spore surface. Although this coalescence may result from the directed collapse of Buller�s drop onto the spore, it may also involve the movement of the spore toward the drop. The release of surface tension at coalescence provides the energy and directional momentum to propel the spore and drop into the air. Analyses show that the initial acceleration of the spore exceeds 10,000 g.