FIGURE 1.

Model of abscission. Simple schematic depicting process of abscission (adapted from Patterson, 2001). Four basic stages are depicted: Stage 1: Determination of the abscission zone, Stage 2: Competence of abscission zone to respond to abscission signals, Stage 3: Activation of abscission or cell separation event leading to organ detachment, and Stage 4: Transdifferentiation of the proximal layer creating a protective layer for plant. (For a more comprehensive model with gene pathways, see Estornell et al., 2013).