The Chopper-Light-System produces intermittent light with common fluorescent tubes. The effect of Chopper-Light on multiplication and shoot development of in vitro shoot cultures of Amelanchier lamarckii and Tilia cordata was investigated at three photosynthetic active photon flux densities (PPFD): 22, 37 and 86 µmol m^-2 s^-1, applied in intervals of 100 ms light/100 ms dark (Chopper-Light) and with the continuous light (control) for a photoperiod of 16h daily. The shoot cultures were cultivated on modified MS-medium containing 30 g l^-1 sucrose. Regardless of the lighting regime, shoot culture multiplication rates and fresh weight increased with PPFD value. There was no difference in multiplication and fresh weight of Amelanchier between Chopper-Light and control at a PPFD of 37 µmol m^-2 s^-1, however, at PPFD of 22 and 86 µmol m^-2 s^-1 multiplication rate and fresh weight in Chopper-Light was reduced compared to the control. In Tilia, no differences in multiplication rate and fresh weight could be found between the two lighting regimes. Generally, in Chopper-Light a higher number of longer shoots were formed.