Nonthermal plasma engineering for seed disinfection and germination using streamer corona and dielectric barrier discharges
Sawita Suwannarat, Sirikan Homkanchan, Jiratchaya Puttha, Siwapon Srisonphan
Abstract
Nonthermal plasma technologies based on electrical discharge, including streamer corona discharge (SCD) and dielectric barrier discharge (DBD) plasmas, offer innovative and sustainable approaches for enhancing seed germination and combating seed-borne pathogens. This study evaluated the application of SCD and DBD plasma treatments to Chinese kale ( Brassica oleracea var. alboglabra ) focusing on germination performance, seed coat modification, and pathogen suppression under optimized electric field intensity, reactive species distribution, and treatment duration. Untreated seeds exhibited germination rates of ∼90 %, with healthy seedling rates of 60 % and infection rates exceeding 40 %. In comparison, SCD plasma, characterized by intense localized electric fields, enabled precise seed coat etching and targeted sterilization, increasing healthy seedling rates to 80 % and reducing infection rates to 20 %. DBD plasma, with its uniform electric field and stable microdischarges, delivered consistent seed coat roughening, scalability for batch processing, and high germination rates of 90–100 % while reducing infection rates to 30 %. Scanning electron microscopy analysis revealed that SCD induced localized etching and thinning of the seed coat by 70–90 %, whereas DBD produced uniform surface roughness and enhanced permeability, essential for breaking dormancy and pathogen suppression. This study establishes the complementary strengths of SCD and DBD plasmas, offering sustainable, chemical-free seed treatment strategies with the potential to support long-term storage viability and microbial safety in agricultural systems.