Seed Germination of Sunflower as a Case Study for the Risk Assessment and Management of Transgenic Plants Used for Environmental Remediation in South Korea

In South Korea, the safety management of living modified organisms (LMOs) is regulated by seven government agencies depending on their use, and the Ministry of Environment is in charge of LMOs to manage environmental remediation and effects on natural ecosystems. This study aimed to develop appropriate research tools to determine the factors affecting the invasiveness of transgenic plants used for environmental remediation. We examined the persistence of sunflower (Helianthus annuus L.) as a candidate by comparing the seed viability at different controlled temperatures and soil depths (ranging from 0 to 30 cm). The germination characteristics of seeds significantly differed between cultivars and temperatures. The field trials indicated that seeds buried at a depth of 30 cm mostly decayed within three weeks, whereas those buried at 0 cm persisted for eight weeks but decayed after sixteen weeks, implying a significant interaction between burial depth and seed persistence. At all soil depths, no dormant seeds were detected over one week after burial. These results suggest that sunflower seeds could not be successfully established under our experimental conditions. Since seeds on the soil surface demonstrated the highest rates of germination, such seeds may require particularly careful management to prevent unintended effects on ecosystems.