Effects of LED Spectra on Morphogenesis, Photosynthetic Pigments, and Phytochemical Composition of Coffea arabica L. In Vitro Cultures

Light quality is an important factor affecting plant growth and secondary metabolite production. This study evaluated the effects of five LED light treatments and fluorescent light (control) on the morphogenesis, photosynthetic pigment content, and phytochemical profile of Coffea arabica L. shoot cultures, and compared their metabolite composition with greenhouse-grown plant organs. Cultures were maintained on MS medium supplemented with 5 µM BA and 0.5 µM NAA under blue (B), red (R), ultraviolet/blue (UV/B), far-red/red (Fr/R), white LED (WLED), or fluorescent (Fl) light for eight weeks. Metabolites were characterized using HPLC-DAD-ESI-MSn and LC-HRMS/MS and quantified by HPLC-DAD. Fr/R resulted in the greatest shoot elongation and multiplication among the tested treatments and produced the highest neochlorogenic acid content (668.80 mg/100 g DW). Fluorescent light favored photosynthetic pigment accumulation, whereas B light produced the highest 4,5-di-O-caffeoylquinic acid content (486.50 mg/100 g DW). Compared with different organs from a single greenhouse-grown plant, in vitro cultures accumulated approximately 30-fold more neochlorogenic acid and 5.5-fold more 4,5-di-O-caffeoylquinic acid, but 7.6-fold less chlorogenic acid. Neither caffeine nor 5-O-feruloylquinic acid was detected in the in vitro cultures. These findings indicate that light quality may be used to regulate shoot development and selectively modify phenolic acid accumulation in C. arabica in vitro cultures.