The influence of the applied photoperiod during floral stem development has been studied. A clear relationship between the length of the photoperiod, the frequency of light/dark switches, and the dynamic of growth and the subsequent morphology and architecture has been found. An increase in the day length (L/D = 16/8) or an increase in frequency of light/ dark transitions (L/D = 7/7) stimulated the inflorescence growth. The two treatments induced the same enlargement in the early inflorescence, but the L/D = 7/7 condition causes a greater increase in the late one. The treatments induced also a diminution in the number of lateral inflorescences, principally with the high frequency light-on/light-off condition. Moreover than differences in the growth along the early inflorescence, at the level of the internode, a gradual growth was observed from the basal part to the upper part of the internode. Finally, the floral stem growth dynamic showed that it could be adapted to the environmental light/dark signaling by a good extension rate synchronisation.