To many people, seed dormancy simply means that a seed has not germinated, but we will soon see that this definition is inadequate. Unfavourable environmental conditions are one reason for lack of seed germination. That is, seeds could be in a paper bag on the laboratory shelf (ie lack of water), buried in mud at the bottom of a lake (ie insufficient oxygen and/or light), or exposed to temperatures that are above or below those suitable for plant growth. These obviously unfavourable conditions for germination are examples of how the environment rather than some factor associated with the seed per se prevents germination. A second reason why seeds may not germinate is that some property of the seed (or dispersal unit) prevents it. Thus, the lack of germination is a seed rather than an environmental problem. Dormancy that results from some characteristic of the seed is called organic dormancy, and this type of dormancy usually is of most interest to seed biologists and ecologists.(Baskin and Baskin, 1998)

The switch to germination represents a transition to or from one stable non-germinating state to another germinating state. As such, germination control can be viewed as a classical bifurcating system with two stable attracting states: non-germination and germination (Tyson et al., 2003). In-between lies a critical unstable transition that is passed as the system flips from the unstable state that provides the borderline (and thus quantifies the critical point for transition) between the two stable ones. The role of