Probable transcription factor involved in the regulation of floral induction under long day (LD) conditions. Promotes photoperiodic flowering by repressing GHD7, a major floral repressor. Seems to function independently of HD1. Interacts with TRX1. Expressed in shoot apical meristem and leaves. Circadian-regulation under short day (SD) conditions. Expression increases after dawn, peaks just before dusk and gradually decreases during the dark period. Late-flowering phenotype under short day (SD) and natural day (ND) conditions. Extreme late-flowering phenotype under long day (LD) conditions.