FIGURE 1.

Photoperiod sensing influences development of plants, induces abiotic and biotic stress tolerance, and causes photoperiod stress. The length of the photoperiod is detected by a sensing mechanism consisting of chloroplasts and photoreceptors, which transfer the light information to the circadian clock. The interplay between the photoperiod and the circadian clock regulates developmental processes, such as flowering, tuberization, bud setting, dormancy, and senescence, and improves the plants’ tolerance to abiotic and biotic stresses. A sudden prolongation of the photoperiod results in photoperiod stress.