The point at which the physiologically controlled phase of plant senescence gives way to the propagating necrochemistry of death needs a term of its own, for which I have proposed acherontic.

In the exploitation of plants by people, acherontic change is often deliberately started and supported.

Malting of cereals, for example, is a process that occupies the twilight zone between viability and death of the grain.

Similarly the retting of fibre crops like flax, and the preservation of fodder by ensilage involve induction of senescence which rapidly moves on to the acherontic  phase of physiological run-down.

There are lots more examples to show that acherontology perhaps should be a study in its own right, addressing the important question as to when biology ends and non-animate chemistry begins.

More of this in H Thomas (2003) Do green plants age and if so how? Topics in Current Genetics 3: 145-171