Effects of Biologically Synthesized Iron Oxide Nanoparticles on Rhizospheric Microorganisms Associated with Tomato (Solanum lycopersicum L.)

Abstract

In this study, the effect of iron oxide nanoparticles on soil rhizospheric microbial communities of tomato was investigated. Iron oxide nanoparticles were biologically synthesized using plant extract from Azadirachta indica, and characterized using a UV-VIS spectrophotometer. Varying concentrations (25, 50, 75, or 100 %) of biosynthesized iron oxide nanoparticles or precursor solution was rhizoinjected into soils in which tomato plants were grown. Plate count method was used to analyse population size and community structure of test subjects. Quantitative analysis of the bacterial and fungal community was determined and diversity indicies were calculated. The results obtained from the analysis revealed that the addition of iron oxide nanoparticles to the soil changed bacterial and fungal community with respect to the control. Also, the bacterial and fungal abundance were changed. Some tolerant microorganisms such as Micrococcus, Stapylococcus, Aspergillus, Trichoderma and Penicillium could withstand high concentrations of iron oxide nanoparticles. Shannon diversity indices showed that there was difference in the diverisity of each concentration of iron oxide nanoparticles for both fungal and bacterial communties. The study's findings showed that high concentration of iron oxide nanoparticles in the soil had adverse effect on both the tomato and the microorganisms associated with the root of the tomato. Further study needs to be conducted to ascertain the magnitude of impact iron oxide nanoparticles will have on plants and rhizosphere microbiome.