Figure 1.
The process of ballistospore discharge.
a, Ballistospore of Tilletia caries a few seconds before discharge. b, Predicted trajectories of spores discharged from a mushroom gill illustrated by A. H. R. Buller [1]. c, Successive images of ballistospore discharge in Armillaria tabescens from video recording obtained at 50,000 fps. Buller's drop (arrowed) carried with discharged spore. Scale bars, a, c, 10 µm b, 50 µm.
Figure 2.
Basidiomycetes selected for this study.
Images of A. auricula and C. pyxidata courtesy of Tom Volk.
Figure 3.
Model spore trajectories for seven basidiomycetes species based on measurements of spore size and launch speed and using Stokes model of viscous drag.
To aid visualization, spores were launched horizontally from arbitrary heights. Positions of spores at 50 µs intervals indicated by dots. The variation in horizontal range predicted from the measured variation in launch speeds (±standard error; Table 1) for each species is represented by the shaded region around each trajectory. Species initials: G.j.-v., Gymnosporangium juniperi-virginianae; T.c., Tilletia caries; S.s., Sporobolomyces salmonicolor; A.a., Auricularia auricula; P.s., Polyporus squamosus; A.t., Armillaria tabescens, and C.p., Clavicorona pyxidata.
Table 1.
Ballistics of spore discharge in seven basidiomycete species.
Figure 4.
Relationship between discharge distance and (a) projectile radius (spore plus adhering fluid), and (b) Buller's drop radius in the seven basidiomycete species examined using high-speed video.
Species initials same as Fig. 3.
Figure 5.
Relationship between spore volume and tube radius.
Scatter plot shows data for 382 species of mushroom-forming fungi (Agaricomycetes) with poroid fruiting bodies. The line indicating least squares fit has an r2 value of only 0.098 (P<0.0001), indicating a poor association between the plotted variables.