Effect of Titania (TiO2) Nanoparticles on the Growth of Spinach (Spinacia oleracea) Under Differing Soil Conditions

Abstract

Nanotechnology has widely been used in a variety of fields including agriculture, since the last
few decades. The aim of the present study was to assess the effect on the growth of Spinach
(Spinacia oleracea) under exposure of 0, 100, 200, 250, 300, 400, 500 mg TiO2 nanoparticles
(TNPs) kg-1 of soil. TNPs in anatase form with a size of 74 nm, complex and spherical in shape
were synthesized. Two different soils 1) Loamy Soil and 2) Sandy Soil were used under low pH
(about 6.5) and high (original) pH of the soils. The effects of TNPs were investigated on plant
lengths, total fresh and dry biomass. The plants were exposed to TNPs for about 3 months. It was
observed that TNPs had a generally negative impact on the length of plants grown in sandy soil
(both low and original pH) and loamy soil with low pH. The measurements of samples with the
original pH of loamy soil showed a positive relationship with increased TNPs concentration.
Overall the dry biomass of plants grew in (both low and original pH) loamy soil and sandy soil
with low pH had increased with increase in concentration of TNPs, while in sandy soil with
original pH, the biomass of plants decreased with increased concentration of TNPs. Phosphorous
analysis on rhizosphere soil showed correspondence with biomass results. Generally, it was
observed that type of soil and pH of soil affected the growth of spinach plants under applied
TNPs.