Meeting Abstract
Because plants lack locomotion, their only means of colonizing new habitats or escaping disease or predation is through seed and spore dispersal. The most effective methods for dispersal over long distances use a fluid to carry propagules. Examples of extremely long-range dispersal include pollen grains kept aloft in the atmosphere and coconuts riding ocean currents for thousands of kilometers. Despite the efficiency of using a fluid to assist in dispersal, some plants have evolved to ballistically launch their propagules at high speed. In these situations, air resistance works to decrease dispersal distance. Here we will show how the fruits of several Acanthaceae species use a dynamic method to gyroscopically stabilize launched seeds to minimize forces from air drag. We will compare this behavior across a number of Acanthaceae species and show how seed morphology and launch dynamics affect launch ranges. We will also show how this same mechanism of stabilizing disk-shaped seeds with backspin is also employed by the unrelated fruits of Hura crepitans (Euphorbiaceae) with a high frame rate video of its explosion. Finally, we will present the spore dispersal of Sphagnum moss where a vortex ring is used to efficiently carry high-drag spores to a height where they can be carried indefinitely by wind currents thus employing both low drag and high drag mechanisms to disperse its spores.
