Spectral Modulation of Morphophysiological Responses and Plant Quality in Korean White Dandelion (Taraxacum coreanum Nakai) Under Controlled Environmental Conditions

This study evaluated the effects of seven light-emitting diode (LED) spectra on the morphophysiological and plant-quality responses of Korean white dandelion (Taraxacum coreanum Nakai) grown for 30 days under controlled environmental conditions. The treatments included monochromatic red, green, and blue LEDs; a purple-phyto LED containing red, blue, and far-red wavelengths; and three white LEDs (warm white, natural white, and cool white). Morphophysiological responses were assessed together with principal component analysis, correlation analysis, and hierarchical clustering. Green light promoted elongation, increasing shoot height and leaf length, but reduced stem diameter, root length, leaf thickness, biomass accumulation, photochemical performance, and plant quality indices. Red light also resulted in relatively low biomass, SPAD units, Fv/Fm, PIABS, normalized difference vegetation index (NDVI), Dickson quality index (DQI), and integrated morphophysiological index (IMI), indicating an imbalanced growth response. In contrast, natural white and cool white LEDs were generally associated with greater stem thickening, root development, leaf thickening, shoot and root dry weight accumulation, and higher Fv/Fm, PIABS, NDVI, DQI, and IMI. Warm white showed favorable trends in shoot and root fresh weights and relative moisture content. Multivariate analyses separated the red and green treatments from the white-light treatments. Overall, white LEDs, especially natural and cool white, appeared more effective than monochromatic LEDs in supporting balanced early growth and plant quality in T. coreanum.