Effects of 60Co-γ Radiation on Root Growth, Active Components, and Antioxidant Capacity of Platycodon grandiflorus Root

Using Chinese purple-flowered Platycodon grandiflorusas the test material, three doses of 60Co γ-ray irradiation (50, 100, and 200 Gy) were applied to investigate their effects on root growth, active component content, and antioxidant capacity. The results showed that in terms of growth, only the 50 Gy treatment group exhibited a significant reduction in fresh weight by 32.61% compared to the control group, while no significant differences were observed in root growth indicators for the 100 and 200 Gy treatment groups. Externally, irradiation did not cause notable changes in the color of the roots. Regarding active components, the total polyphenol content increased significantly by 16.53% and 16.86% in the 50 and 200 Gy treatment groups, respectively, whereas the flavonoid content decreased by 11.07% in the 100 Gy group. The platycodin D content increased significantly in all treatment groups, while components such as total polysaccharide showed no significant changes. HPLC fingerprinting and similarity analysis indicated consistent chemical compositions across all groups, suggesting that irradiation did not affect material stability. Antioxidant capacity analysis revealed that irradiation significantly enhanced DPPH free radical scavenging ability and total reducing power. Comprehensive studies indicate that a radiation dose of 200 Gy significantly promotes the accumulation of active ingredients in Platycodon grandifloras while ensuring normal root growth and compositional safety, making it a candidate dose for radiation-induced mutation breeding aimed at improving medicinal quality. This study explores the radiobiological effects of 60Co γ-rays on the roots of Platycodon grandiflorusand provides a theoretical basis for its mutagenesis breeding.