LED Exposure Modulates the Biosynthesis of Silver Nanoparticles from Root Tuber Extract of Chlorophytum borivilianum and their Phytotoxicty.

The present study reports an efficient phyto-mediated and photo-catalyzed synthesis of silver nanoparticles (AgNPs) from root tuber extract of Chlorophytum borivilianum and demonstrates its phytotoxicity during seedling growth of Peltophorum pterocarpum. A time course analysis of the appearance of SPR peak during incubation of reaction mixture under the exposure of various light treatments suggested the influence of light spectral quality on the biosynthesis of AgNPs. Irradiation of reaction mixture with blue LEDs (BL) induced the rapid synthesis of spherical particles smaller in size compared to other treatments. The reaction mixture optimized for the synthesis of AgNPs remains same for all the exposure conditions. FTIR spectra indicated the presence of steroidal saponins and their influence in bioreduction and capping of biosynthesized AgNPs. A bioreduction mechanism insensitive to the variations in spectral quality was proposed suggesting borivilianoside H, a steroidal saponin, as the bioreductant. The toxic impact of AgNPs was more pronounced with the particles synthesized under BL exposure particularly at rooting stage. The findings suggest the influence of LED lighting not only on the biosynthesis of AgNPs but also on its phytotoxicity. [ABSTRACT FROM AUTHOR]