During the last phase of sprouting, the elevated propagule straightens as it becomes vertical. This is accomplished by elongation of the inner radius of curvature. At this point, too, the epicotyl bud swells and the shoot emerges... this is NOT developmentally linked to the elevation itself (see text).
At this point, the epicotyl-less propagule has developed an adventitious bud. In general, mangroves do not retain the capacity for that for very long. The restrained propagules also develop leaves and begin to pull their bases from the soil (it is a bit hard to see).