Blue and red light-emitting diodes with or without sucrose and ventilation affect in vitro Growth ofRehmannia glutinosa plantlets

Single-node, in vitro cuttings ofRehmannia glutinosa were transplanted to MS basal media and grown for 30 d. Plantlets were grown under various culture conditions: four different light qualities (red LEDs, blue LEDs, mixed LEDs, and fluorescent); with sucrose (30 mg.L^-1) or without (0 mg.L^-1); with air exchanges (3.5 h.^-1) or without (0.1 h.L^-1). Highest dry weights were obtained from plantlets under blue LEDs with 3.5h.L^-1 air exchanges. Light source did not affect shoot elongation in ventilated conditions, but without ventilation, the shoots of plantlets under red LEDs were twice as long as for plantlets growing under other types of lighting. Plantlets grown without sucrose showed little difference in photosynthesis under any of the tested light qualities. In contrast, the photosynthetic rate of those in the sucrose-containing media varied according to light source.