Stem elongation and somatic embryogenesis under red light-emitting diode and subsequent growth of tuberous begonias (Begonia x tuberhybrida Voss) plantlets on medium containing cobalt nanoparticles

The stem elongation, somatic embryogenesis of Tuberous begonias (Begonia x tuberhybrida Voss) plantlet under different lighting (fluorescent lamps - FL, blue light-emitting diode - LED, red LED and blue to red LED ratio), and subsequent growth on medium containing cobalt nanoparticles were investigated. The results showed that shoots (1.5 cm in length) cultured under the red LED condition produced higher values of shoot length (6.13 cm), number of internodes per shoot (6.00 internodes), fresh and dry weights (640.34 mg and 78.25 mg, respectively) compared to those under the other lighting conditions after 60 days of culture. Meanwhile, the S-tTCL explants cultured under red LED achieved higher somatic embryogenesis (64.71%), number of somatic embryos (46.67 embryos) and percentage of somatic embryos with torpedo-shape (34.39%) and cotyledon (65.61%) as compared to those under the other lighting conditions after 60 days of culture. For plantlet formation and subsequent growth, somatic embryos (cotyledon shape) cultured on medium containing 0.0465 mu g/L CoNPs enhanced plantlet growth, acclimatization and flowering of plantlets in the greenhouse. Key messageRed light-emitting diodes enhanced stem elongation and somatic embryogenesis of tuberous begoniaMedium containing cobalt nanoparticles enhanced plantlet growth and their acclimatization