Development of copper sulfide-sepiolite nanocomposite (SP-CuS NC) as degradable, assimilative and hypotoxic antifungal seed storage material

Abstract

Challenges activated engineered nanoparticles composites are attracting increasing attention as next generation seed storage materials to retain or increase seed viability, in light of unavailability of seed storage chemicals. Copper sulfide-sepiolite composite (SP-CuS NC) nanoplatform was developed as seed treatment agent to control seed borne fungal pathogen as well to increase the seed quality parameters after application during storage. Copper sulfide-sepiolite nanocomposite (SP-CuS NC) was prepared sonochemically by in situ synthesis of copper sulfide in aqueous media containing dispersed activated sepiolite. The complete topomorphological, elemental and bonding information was obtained from TEM, SEM, EDS mapping, AFM, XRD, IR and UV–visible spectroscopic methods. Results from application of nano composite on freshly harvested paddy seeds at different active concentrations of copper sulfide (ranging from 20 to 500 μg/g) when packed in cotton bags for storage indicated the efficacy of such nano-enabled natural silicate material for seed storage approach due to the restricted delivery of copper at the right place without showing any sign of phytotoxicity. SP-CuS NC inflicted the promotion of seed germination, particularly in the diseased media conditions, which increased with the time of application as well as applied concentration. The most optimized concentration was 500 μg/g for the application of six months in which % enhancement in germination, root length, shoot length, dry weight and vigor index were maximum at 70.92%, 73.69%, 69.65%, 52.21% and 86.14%, respectively (comparison to control) (P-value < 0.05). The % reduction in seed blight and seed rot were 88.17 and 89.81 which was also maximum at the same applied concentration and time of application. SP-CuS NC significantly increased the health and quality parameters of rice seeds as compared to conventional copper formulation which becomes toxic at the comparative concentrations.