Cold Plasma Treatment for Astragalus membranaceus Seed Germination and Seedling Growth Improvement

Background: Astragalus membranaceus seeds have dormant properties that not only limit germination but also negatively affect the growth of seedlings. We investigated the enhancing effect of cold plasma treatment on seed germination and the positive effect on seedling growth of Astragalus membranaceus by treating its seeds with cold plasma at different power levels. Method: The Astragalus membranaceus seeds were treated with cold plasma at power levels of 40, 60, 80, 100, 120, 140, 160, 180, 200, 220 and 240 W for 15 seconds with helium gas and seeds without any treatment were used as control. Results: The Astragalus membranaceus seeds were treated with cold plasma, which not only improved seed germination, but also had a positive effect on seedling growth, with the best results for the 80 W power cold plasma treatment. The 80 W power cold plasma treatment increased the germination rate, germination index and vigor index of Astragalus membranaceus seeds by 26.8%, 12.4% and 39.8%, respectively; increased root length, CAT activity and SOD activity of Astragalus membranaceus seedlings by 24.5%, 99.7% and 7.1%, respectively and decreased the relative conductivity and MDA content of Astragalus membranaceus seedlings by 6.6% and 17.6%, respectively; compared with that of the control group.