Impact of monochromatic lights on the in vitro development of Cattleya walkeriana and effects on acclimatization

Abstract Light quality is an important factor for the adequacy of plant production through plant tissue culture, as it directly interferes with morphogenesis and photosynthetic capacity of explants. The objective of this study was to analyze the impact of monochromatic lights such as light emitting diode (LED) on the in vitro development of Cattleya walkeriana G. and their effects on acclimatization. The plants were developed in vitro under the colors of green, blue, yellow, red, 2 red:1 blue, and white LED lights. For in vitro cultivation, Knudson medium was used, supplemented with 20 mg L-1 sucrose, 5.5 mg L-1 agar, 2% activated charcoal, 100 mL coconut water, and pH 6.0. For ex vitro cultivation, the plants were acclimatized in styrofoam trays containing sphagnum as a substrate. In general, the supplied light lengths impactedin vitro growth and acclimatization analyses. There was influence on the cuticle thickness of plants in vitro. Chlorophyll and carotenoid contents were not significant. We can conclude that light lengths formed by 2 red:1 blue, red and yellow LEDs can be indicated for better performance in the production of C. walkeriana. The 2 red:1 blue and red LEDs provide superior in vitro development than the others, with gains for the species in acclimatization. The yellow LED provided a possible in vitro hardening, which ensured the greatest success of the seedlings during acclimatization.