Light spectrum variations: Implications for growth and bioactive compound synthesis in Trigonella persica

Abstract

The advent of light-emitting diodes (LEDs) has significantly advanced research on plant growth and productivity. This study investigated the effects of various light sources—including fluorescent, blue, red, and a blue-red (1:1) LED combination—on the growth and bioactive compound production in Trigonella persica during its vegetative phase. Results showed that red and blue-red light significantly enhanced growth, whereas blue light (BLR) adversely affected plant development. High-performance liquid chromatography (HPLC) analyses demonstrated a significant reduction in the levels of indole acetic acid (IAA) and brassinosteroids (BR) under BLR conditions. Assessments of oxidative stress markers, including hydrogen peroxide (H₂O₂), malondialdehyde (MDA), and antioxidant enzymes (catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and superoxide dismutase (SOD)), revealed significant alterations in response to the different light conditions. Gas chromatography-mass spectrometry (GC-MS) analyses indicated that light conditions influenced the production of bioactive compounds, with higher total bioactive compound levels (approximately 72% of the total extract) in plants grown under fluorescent light compared to LED treatments. Light and scanning electron microscopy (SEM) analyses revealed a lack of glandular trichomes in leaves under all lighting conditions. In conclusion, pink fluorescent light significantly enhances bioactive compound production in T. persica compared to blue and red LED radiation.