Light and culture medium formulations for in vitro germination and development of Brassavola perrinii¹

Luz e formulações de meio de cultivo na germinação e desenvolvimento in vitro de Brassavola perrinii

ABSTRACT

- The improvement of in vitro propagation techniques using appropriate artificial light sources and culture medium formulations is important to allow the mass production of individuals with high genetic variability. Thus, this research aimed to study the effect of light sources from fluorescent lamps and light-emitting diodes (LEDs) and culture medium formulations on the germination and initial development of the orchid species Brassavola perrinii. The experiment was set up in a completely randomized design in a 5 × 4 factorial scheme, consisting of five light sources – fluorescent lamp (100%), white LED (100%), blue LED (100%), red LED (100%), and blue LED (50%) + red LED (50%) – and four culture medium formulations – MS, ½ MS, VW, and K –, with four replications and a mean of 125 seeds per plot. The percentage of germination, chlorophyll protocorms, and protocorm development through the classes P1, P2, P3, and P4 to calculate the protocorm development index were evaluated at 90 days after sowing. The data were subjected to analysis of variance and the means were compared by the Tukey test (p < 0.05). The percentage of germination for B. perrinii was not influenced by light spectra but was higher in the ½ MS and VW formulations. The highest protocorm development index of B. perrinii was observed when the species was submitted to the light spectrum of the lighting source with fluorescent lamps in the VW culture medium.

Keywords:
Light sources; Protocorm; Asymbiotic sowing; In vitro sowing