Abstract
<title>Abstract</title> <p>Light spectral quality directly influences growth, photosynthetic physiology, and acclimatization processes in orchids cultivated in vitro. In this context, the present study aimed to evaluate the effects of different light spectra on the morphophysiological development of Gomesa flexuosa plantlets cultivated in vitro and during ex vitro acclimatization. Plantlets were exposed to different light qualities provided by light-emitting diodes (LEDs), including white, blue, red, and combined spectra. Morphometric traits, photosynthetic pigments, chlorophyll a fluorescence, and photosynthetic performance were evaluated throughout in vitro cultivation and after acclimatization. The results demonstrated that spectral quality significantly modulated plant physiological and structural responses. Red light promoted greater leaf emission and vegetative growth, whereas blue light increased chlorophyll and carotenoid contents and improved the photochemical efficiency of photosystem II. Plants grown under combined spectra showed intermediate responses and greater physiological balance during acclimatization. Chlorophyll fluorescence parameters indicated higher photosynthetic stability under blue and blue/red light treatments, evidencing lower photoinhibition occurrence. It can be concluded that manipulating light spectral quality is an efficient strategy to optimize in vitro cultivation and improve ex vitro adaptation of Gomesa flexuosa, contributing to more efficient protocols for micropropagation and conservation of ornamental orchids.</p>