Spectral regulations with light-emitting diodes: modulating photosynthesis, nutritional quality, and secondary metabolite biosynthesis in fenugreek microgreens

This study evaluates the effect of light-emitting diode (LED) sources on photosynthesis, nutritional quality, and primary and secondary metabolites in the microgreen fenugreek ( Trigonella foenum-graecum ). Under three light combinations- sunlight as the control (L 1 ), white light (L 2 ), and LED (Red: White: Blue) (L 3 )- morphological measurements showed numerical variations, where L 2 treatment enhanced plant height of fenugreek by 25.8%, while L 3 exhibited increased total chlorophyll content by 27.9% compared to the control, whereas carotenoid content was found balanced among the treatments, reflecting improved photoprotection. Leaf and root dimensions varied numerically among light treatments, although these differences were not statistically significant. In addition, fenugreek greens grown under LED light showed a 31.5% increase in total soluble protein compared with the control, qualitatively validated by SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis). Photosynthetic proteins such as PSI, PSII, and cytb6 were examined by BN-PAGE (blue-native polyacrylamide gel electrophoresis) and immunoblotting of PS1-A, indicating distinct differences across treatments. Further, LED treatment (L 3 ) increased primary metabolite levels compared to L2, and the control was followed by secondary metabolite analysis using GC-MS. Overall, LED treatments showed statistically supported effects on photosynthetic pigments and soluble protein accumulation, while morphological and proximate nutritional parameters exhibited numerical trends that require further validation. These findings show the significance of integrating environmental controls for high-quality, efficient microgreens cultivation in precision agriculture.