Morphological Changes

Morphological changes during the transition from the globular stage to the heart stage are the first visible sign of the formation of the two embryonic organ systems: the cotyledons and the axis. The emergence of the cotyledons from a radically symmetrical globular embryo indicates that groups of cells in the apical region are induced to proliferate at specific sites. Polar auxin transport may be involved in directing these localized cell divisions.

Transition from globular stage embryo to the heart stage embryo.