Banana pulp and peel as biostimulants under LED lighting for the in vitro growth of Laelia gloriosa Rchb.f.

The efficiency of in vitro culture of native orchids still depends on the optimization of culture media and lighting conditions, particularly regarding the use of organic supplements with biostimulant potential. This study aimed to evaluate the effect of biostimulants based on the pulp and peel of different banana cultivars, combined with different LED light color temperatures, on the in vitro growth of Laelia gloriosa (Rchb. f.). The experiment was conducted in a completely randomized design in a 2 × 9 factorial arrangement, consisting of two LED lighting systems (3,000 K and 6,500 K) and nine MS media, either unsupplemented or supplemented with pulp or peel of the banana cultivars ‘Nanica’, ‘Maçã’, ‘Prata’, and ‘da terra’, with four replicates. After 120 days, the following variables were evaluated: plant height, longest root length, longest leaf length, fresh mass, number of pseudobulbs, number of leaves, and number of roots. A significant interaction between the factors was observed for all variables analyzed. Overall, LED lighting at 3,000 K promoted greater plantlet growth. The medium supplemented with nanica banana pulp stood out for vegetative growth and biomass accumulation, whereas nanica banana peel favored rooting. For the number of pseudobulbs and leaves, the unsupplemented MS medium showed the best results. Growth patterns reflected differences in banana nutritional composition, especially in carbohydrate and mineral contents. In conclusion, the use of banana-based biostimulants associated with 3,000 K LED lighting represents an efficient and low-cost strategy for the in vitro propagation of L. gloriosa.