Molecular Mechanisms of Photoperiod Actions on Plant Flowering

Day-length sensing is an important biological function in plants and photoperiod is one of the key ambient factor determining the time of plant flowering.The darkness length in photoperiod is the crucial factor determining the formation of plant flowers.Morphological and genetic analysis revealed some photoperiod-sensitive genetic characteristics in plants and confirmed the criteria of photoperiodism index.In the meantime,the molecular marker linkage map of photoperiod-related trait was established and became important basis in gene localization,cloning and molecular marker-aided selection as well as an effective approach to studying photoperiod mechanism.And a genetic approach to helping long-day plants to flower was set up by studying modular Arabidopsis thaliana.The mechanism of the approach was summarized as follows:light and light-sensitive information were combined to form and transfer signals so that CO expression was activated.On the basis of the variation in daily day-length cycle,light system and genetic background,CO activated FT expression and then led to flowering occurrence given that CO expression and daylength were well coordinated.Some advances in photoperiod mechanism have been made in such crops as rice,wheat and corn.