S3-3 Friday, Jan. 4 09:00 - 09:30 The Role of Water in Effecting Rapid Movements in Plants EDWARDS, J; Williams College firstname.lastname@example.org
Plants lack muscles, yet can carry out extraordinarily rapid movements in the order of milliseconds or less. Many of these ultra fast movements are mediated by water. Here I compare the rapid movements of three plants: the liverwort, Marchantia polymorpha; the moss, Sphagnum spp.; and the flowering plant, Cornus canadensis (bunchberry dogwood). Each uses specialized morphological features and the movement of water to effect ultra rapid movements, which are used to disperse spores or asexual reproductive propagules. These species illustrate three different ways that water can bring about rapid movement in plants. Marchantia directly harnesses the kinetic energy of falling raindrops to propel gemmae (asexual reproductive propagules) from hour-glass shaped gemma cups. For Sphagnum, water loss from the capsule walls causes the capsule walls to shrink and build up internal air pressure in the capsule. The result is a sudden explosion that disperses spores in a vortex ring. Finally, the petals and stamens of bunchberry dogwood build up turgor pressure putting both petals and the stamen filaments under tension. Visits by insects release the stored mechanical energy and result in explosive flowering opening and pollen (spore) dispersal from the trebuchet-like stamens.