Simulation model of a possible trigger for reversible switching of the stress regime in plants

A simulation model of a trigger mechanism that reversibly switches a plant to the stress regime in response to adverse environmental effects is sugges ted and investigated. This mechanism is activated by an elevated level of s pecific cell metabolites and, by inhibiting the customary synthetic process es, actuates the formation of systems that counteract the deregulation of p lant metabolism. The operation of the postulated mechanism corresponds bett er to the known patterns of plant transition between the normal and stress states than the operation of common triggers. The model describes the rever sibility of stress response and its relation to the intensity of environmen tal effects. The model also suggests that the stress response in plants is aimed at stabilizing the cell level of "dangerous" stress metabolites under adverse environmental conditions and providing for the termination of plan t stress after cessation of the action of a stress factor. The possible act ual prototypes of the model variables are discussed and used to explain sev eral phenomena observed in plants under stress conditions, in particular, t he changes in the system of prooxidant-antioxidant equilibrium.