Induction and characterization of embryogenic calli of Libidibia ferrea un-der LED lighting for in vitro plant regeneration

Resumen

The present study aimed to develop an efficient protocol for indirect somatic embryogenesis in Libidibia ferrea, an Amazonian species of high ecological and pharmacological value. For callus induction, embryonic axis explants were cultured for 45 days on a medium supplemented with different concentrations of the growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D) under three light conditions: red-blue LEDs, white LEDs, and darkness. During the maturation phase, the calli were transferred to a medium containing 10 mg L-1 of abscisic acid (ABA) for 15 days, followed by 30 days on a medium supplemented with combinations of benzylaminopurine (BAP) and indole-3-acetic acid (IAA). Callus formation was observed from the 15th day of culture, with the highest induction rate (93.3%) obtained using 5.0 µM L-1 of 2,4-D under red-blue LED light. During maturation, the formation of pro-embryogenic masses and embryos at the globular and torpedo stages was observed. The combination of 13.31 µM L-1 BAP and 2.85 µM L-1 IAA resulted in the highest number of embryogenic calli, although complete conversion into plantlets was not achieved. In total, 31% of the induced calli exhibited embryogenic potential. The developed protocol proved effective for inducing embryogenic calli, representing a methodological advance for the in vitro propagation of L. ferrea. The results highlight the potential of combining plant growth regulators and LED lighting in somatic embryogenesis; however, further optimization of subsequent stages is required to achieve complete plantlet regeneration, which may support future applications.