During the first phase of sprouting (resumption of growth activity by quiescent hypocotyls), propagules elevate and relax in a diurnal fashion, up during the day and down at night. The movements likely result from alternating hydration and partial dessication of the propagule, made possible by soil contact at the base. The end of this phase coincides with the penetration of the soil by the adventitious roots.
Play this movie a couple of times. After watching the propagule at the front, watch the dead one (same orientation, second box).