FIGURE 1.

Anticipated redox state and circadian rhythms response to abiotic stress in plants. When cells are healthy, plants are in a dynamic equilibrium with the environment and the clock promptly resonates with environmental cycles (A). At stress occurrence, changes in the redox state compromise cellular homeostasis, leading to a state of disequilibrium, with almost unknown consequences on the clock (B). During a phase of recovery or strain, plants try to cope with the stress but how the clock behaves during this time is still uncertain (C). A successful recovery will lead to a new dynamic equilibrium (acclimation) after stress exposure (D). When acclimated, plants maintain a state of memory for which they will possibly experience fewer disturbances from the next stress event (E). In both acclimation and memory state the clock will maintain its functions but very little is known on its possible phase shifts (D,E). On the contrary, if the stress becomes exceptionally destructive, the clock will succumb, plants will not recover and die (F). Solid arrows point to the most certain consequences of stress occurrence; dotted lines point to the possible consequences of recovery after stress; and dash/dotted lines point to the underlying mechanism of memory. Working clocks are coupled with identified physiological states of equilibrium while clock with the question marks represent the states where clock behavior is completely unknown. The red cross signifies the complete disruption of the clock when plants die. The yellow lightening bolt represents stress occurrence.