Abstract
BACKGROUND: A rapid, cost-effective, and eco-friendly method was investigated to enhance the germination potential of lemon basil (Ocimum africanum Lour.) seeds using radiofrequency (RF) cold plasma treatment, addressing poor germination due to seed dormancy in the CIM-Jyoti variety. METHODS: Lemon basil seeds (variety CIM-Jyoti) were treated with RF cold plasma using Oxygen (O(2)), Argon (Ar), and Ar + O(2) gas combinations, varying RF power (W1: 60 W, W2: 150 W, W3: 240 W), process pressure (P1: 0.2 mbar, P2: 0.4 mbar, P3: 0.6 mbar), and treatment time (T1: 5 min, T2: 10 min, T3: 15 min). Germination percentage, seedling vigor indices (SVI-I and SVI-II), and water absorption efficiency were evaluated, with seed surface morphology analyzed via scanning electron microscopy (SEM). RESULTS: The Ar + O(2) gas combination at P2W3T2 treatment resulted the highest percent improvements in germination, SVI-I, and SVI-II by 24.5%, 44.0%, and 69.4%, respectively over control and that highest water absorption efficiency after 10 h of soaking and SEM analysis confirmed this was due to surface etching. O(2) gas treatment at P1W2T2 increased germination by 16.3%, SVI-I by 24.3%, and SVI-II by 24.7% compared to the control. Ar gas treatment at P1W2T1 improved germination by 13.3%, with SVI-I and SVI-II enhanced by 29.6% and 23.0%, respectively at P1W2T2. CONCLUSIONS: RF cold plasma treatment with the Ar + O(2) gas combination proved most effective for enhancing lemon basil seed germination and vigor than using these gases all alone, offering a sustainable alternative for improving seed performance.