Confocal microscopic and nuclear magnetic resonance (NMR) spectroscopic studies of tea leaves treated with green synthesized silver nanoparticles

Abstract

Biological synthesis of silver nanoparticles was done using culture filtrate of Trichoderma asperellum, a potential fungal antagonist taking 1Millimolar silver nitrate solution as the precursor. The synthesized nanoparticles were characterized using UV-VIS Spectrophotometer, Dynamic Light Scattering, Zeta sizer, Transmission Electron Microscope and Energy Dispersive X-ray analysis. The results showed a characteristic Surface Absorption Band at 420 nm which confirmed the formation of silver nanoparticles. The charge of silver nanoparticles was found to have a negative potential value of -1.34 mV and indicated stable on dispersion. The nanoparticles were uniform and well-dispersed in nature with a spherical shape. The average particle size recorded was 8.26 nm with a size range from 4-14 nm and the biosynthesized material contained 32.18% silver, 10.16% oxygen, and 57.66% carbon. The Silver nanoparticles were introduced into 4-5 months old tea seedlings by foliar spray technique and control was maintained by spraying distilled water. After 45 days of treatment leaf samples were collected from both the treated and control plants and subjected to Nuclear Magnetic Resonance Spectroscopic and Confocal Microscopic studies. Presence of silver nanoparticles was detected inside the treated leaf sample and some extra metabolites were reported in treated sample than that of the control sample.