Antifungal Effect of Buxus sinica Leaf Extract-mediated Silver Nanoparticles against Curvularia lunata

摘要

Buxus sinica leaf extract was used to synthesize silver nanoparticles, and leaf extract volume, concentration of AgNO 3 , and pH value were adjusted to ascertain the optimized biosynthesis system, it included 20 mL of leaf extract, 4 mM AgNO 3 , and pH of 7. Transmission Electron Microscopy (TEM) images revealed that the silver nanoparticles were spherical and finely dispersed, with an average size of 5.6 nm. SEM (Scanning Electronic Microscopy) and EDX (Energy-dispersive X-ray) further confirmed their morphology and purity. As-synthesized silver nanoparticles exhibited prominent antifungal activity against Curvularia lunata. At a dose of 200 μg mL -1 of silver nanoparticles, the inhibition rate of colony growth reached 85% and an IC 50 value of 26 μg mL -1 . Furthermore, an inhibition of 100% conidial germination and IC 50 of 9.16 μg mL -1 were achieved at 50 μg mL -1 . Silver nanoparticles exerted destructive effects on mycelial morphology, which became expanded and distorted. The silver nanoparticles effectively prevented the germination of and infection by conidia of C. lunata. It is possible to screen silver nanoparticles as one kind of high efficient fungistatic agent to assist or replace chemical pesticide.