The Effect of Light Quality on Growth and Development of In Vitro Plantlet of Stevia rebaudiana Bertoni

Abstract

Fluorescent lamps are the most commonly used light source for the in vitro culture of various plant species. However, there are other sources of illumination, such as light-emitting diodes (LEDs), which have proven to be more efficient for in vitro culture. In the present study, we evaluated the effect of LEDs on the in vitro morphogenesis, proliferation of shoots, growth and rooting of Stevia rebaudiana Bertoni. For that, five different sources of light were tested under a 16-h photoperiod: fluorescent lamps (Fl), white LEDs (W), red LEDs (R), blue LEDs (B) and a combination of blue and red LEDs (B/R, 1:1). The proliferation rate was higher with R LEDs compared with Fl light, although shoots have a lower length under R LEDs. Under B/R LEDs, maximum shoot elongation was obtained. During rooting, LEDs did not improve the rooting of shoots but increased the content of photosynthetic pigments, which contributed to the acclimation process of in vitro plantlets. Our results revealed that the spectrum of different light sources produced different effects during the in vitro culture of S. rebaudiana.