The possible role of cyclic AMP (cAMP) in plants has been an area of c
ontroversy for nearly 20 years: although cAMP and putative components
of its synthesis, degradation and site of action can be demonstrated,
there has been no clear identification of a signal transduction pathwa
y dependent upon cAMP in plants. However, stronger evidence is accumul
ating for its possible role in stress signalling.