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.

No abstract

No abstract

No abstract

No abstract

No abstract

No abstract

Vanilla planifolia Jacks. is a species of great economic importance, since vanillin, a compound highly valued in the food and pharmaceutical industry, is extracted from its pods. This species is in the category of special protection, so it is important to take actions for its conservation and to maintain the genetic stability of the conserved germplasm. An adequate way to achieve this is through the minimal growth in vitro conservation techniques. The present work aimed to establish an in vitro conservation protocol for vanilla germplasm that allows the genetic stability of the conserved material. For the establishment of the minimal growth in vitro conservation protocol: two concentrations of basal Murashige and Skoog (MS) medium (50% and 100%), two incubation temperatures (4 and 22 °C) and two concentrations of abscisic acid (ABA) (3 and 5 mg⋅L−1) were evaluated. To evaluate the genetic stability of the germplasms used in this study (cultivated, wild, and V. insignis morphotypes) by analyzing the profiles of molecular markers SSR (simple sequence repeats) and ISSR (inter simple sequence repeats). The MS medium (100%) supplemented with 3 mg⋅L−1 of ABA and incubated at 22 °C, was the best treatment for the in vitro conservation of Vanilla spp. Compared with the control treatment, it allowed us to obtain smaller shoots (1.17 × 0.17 cm), which showed high genetic stability, given by the low percentages of polymorphism detected in morphotypes cultivated and wild (SSR 0%, ISSR 2%) and V. insignis (SSR 0%, ISSR 0%). We conclude the usefulness of the established protocol to conserve the genetic variation of the evaluated Vanilla germplasm.