Selaginella Dispersal Biomechanics

In collaboration with the Rosario Lab, we plan (post-quarantine) to study the dispersal biomechanics of the only living genus of terrestrial heterosporous plants: Selaginella. Dispersing large spores is challenging, as most spore-producing plants are short-statured and must rely on abiotic dispersal vectors (either wind or water). Water will carry spores of any size great distances, but what about free-sporing plants that live on land? Relying on the wind to disperse larger spores may not be enough. Some Selaginellas, which produce large megaspores (~200-1000um) have evolved active dispersal mechanisms to shoot spores higher into the air (therefore increasing potential dispersal distance) and some even fling entire sporangia away from the parent plant in a rapid motion not unlike a catapult. 

This "sporangium ejector" mode of spore release is particularly interesting, not only for the fantastic sight it creates (see the video to the right), but also because the mechanism that causes this ejection is the most poorly understood of any of the active spore dispersal mechanisms Selaginella uses. With this project, we are using high-speed video (methodology frequently employed by those who study the biomechanics of rapid movements in animals, such as the famous mantis shrimp strike) to determine exactly how these plants pull off these rapid movements that must generate so much force.