Friday, February 20, 2009

Biomechanics of Fungi

Here's an interesting paper from PNAS at the end of last year: Explosively launched spores of ascomycete fungi have drag-minimizing shapes.

The drag experienced by these fungal spores is within one percent of the absolute minimum possible drag for their size. But these shapes are seen only among spores distributed by air flow, not those which are dispersed by animals.

An optimal drag-minimizing shape ensures that the spores can traverse several millimeters of still air surrounding the fungus' fruiting body; once past that point, the 10-micron spores are light enough to be propelled by even the gentlest breeze.

Also at the end of last year, in PLoS ONE, The Fastest Flights in Nature: High-Speed Spore Discharge Mechanisms among Fungi. Using ultra-high-speed video cameras the launch process in four species of fungi that grow on the dung of herbivores was documented. One of these species was the Pilobolus I mentioned in class. Launch speeds ranged from 2 to 25 m s−1 and corresponding accelerations of 20,000 to 180,000 g propelled spores over distances of up to 2.5 meters.

Don't forget the Lotusland trip tomorrow. 1pm sharp by the Old Little Theater. Weather forecast for Saturday is currently cloudy with a 10% chance of precipitation although the afternoon looks like it should stay dry.

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