Green Synthesis and Characterization of Zinc Oxide Nanoparticles Using Eucalyptus globules and Their Fungicidal Ability Against Pathogenic Fungi of Apple Orchards.

Hilal Ahmad,Nagaraja Geetha,Narasimhamurthy Konappa,Boregowda Nandini,Krishnan Venugopal,Hosur Gnanaprakash Pushpalatha,Arakere C Udayashankar,Savitha De Britto,Kalyanaraman Rajagopal,Sudisha Jogaiah

doi:10.3390/biom10030425

Abstract

Eucalyptus globules belonging to the Myrtaceae family was explored for the synthesis of zinc oxide nanoparticles and for biological applications. The aqueous extract of the synthesized zinc nanoparticles (ZnNPs) was characterized using UV-visible spectrophotometer, FTIR, SEM and TEM. The aqueous broth was observed to be an efficient reducing agent, leading to the rapid formation of ZnNPs of varied shapes with sizes ranging between 52–70 nm. In addition, antifungal activity of the biosynthesized ZnNPs was evaluated against major phytopathogens of apple orchards. At 100 ppm of ZnNPs, the fungal growth inhibition rate was found to be 76.7% for Alternaria mali, followed by 65.4 and 55.2% inhibition rate for Botryosphaeria dothidea and Diplodia seriata, respectively. The microscopic observations of the treated fungal plates revealed that ZnNPs damages the topography of the fungal hyphal layers leading to a reduced contraction of hyphae. This considerable fungicidal property of ZnNPs against phytopathogenic fungi can have a tremendous impact on exploitation of ZnNPs for fungal pest management and ensure protection in fruit crops.

Highlights

Nanoparticles are designated as an extension stuck between bulk material and atomic or molecular compositions
Change in color from colorless to pale yellow was due to the phenomenon of resonance plasmon absorption transitions, which is considered as the primary indication of Zinc nanoparticles (ZnNPs) formation
The consequence of additional characterization process like Scanning Electron Microscopy (SEM) and TEM demonstrated that the ZnNPs were spherical or globular shaped with the undefined varied size of 52-70 nm

Summary

Introduction

Nanoparticles are designated as an extension stuck between bulk material and atomic or molecular compositions. The lesser mass and widespread surface to volume ratio of nanoparticles reveal their significant properties with purposeful applicability in the field of sensors, medical, catalysis, optical devices, DNA labeling and drug delivery. Zinc nanoparticles (ZnNPs) have shown to be having magnificent applicability in molecular diagnostics, detection and micro-electronics [5], and in drug delivery and bioimaging probes [6]. They show exclusive optical and electrical properties [7] due to which, they have various applications in, cosmetics, gas sensors, solar cells, catalysts and ceramics [8], biosensors [9], and solar cells [10]. ZnNPs are considered to be top photocatalysts, which are employed in sanitizing wastewater, and decay or reduce herbicides and pesticides [1]

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