1Department of Plant Science, Faculty of Science, Shahrekord University, I.R. Iran, Department of Medical Laboratory Science, College of Science, Knowledge University, Kirkuk Road, Erbil 44001, Iraq
2Department of Plant Science, Faculty of Science, Shahrekord University & Research Institute of Biotechnology, Shahrekord University, Shahrekord, I.R. Iran
3Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, I.R. Iran
4Department of Medical Laboratory Science, College of Science, Knowledge University, Kirkuk Road, Erbil 44001, Department of Biology, College of Science, Salahaddin University-Erbil, 44002 Erbil, Iraq
5Department of Biology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
چکیده
Recent advancements in LED technology have created new opportunities for cultivating medicinal plants in controlled environments. This study compares the growth of two lemon balm genotypes under four different LED light treatments with standard greenhouse lighting conditions. The photoperiod was set at 18 hours of light and 6 hours of darkness, with a photosynthetic photon flux density (PPFD) of approximately 300 µmol/m²/s and an average temperature of 25 to 35 °C. The experiments were conducted using a completely randomized design, design, consisting of five treatments of light quality and three replications. The primary variables assessed included shoot fresh weight, shoot dry weight, chlorophyll content, carotenoid levels, and the concentration of oxidative stress marker metabolites, specifically hydrogen peroxide (H2O2) and malondialdehyde (MDA). The results showed that red+blue LED lighting increased shoot fresh weight, shoot dry weight, chlorophyll, and carotenoids while minimizing the levels of H2O2 and MDA, indicating reduced oxidative stress. These findings demonstrate that red+blue LED lighting is optimal for promoting growth and antioxidant capacity, thereby enhancing the quality of lemon balm plantlets compared to those grown under greenhouse conditions.