Abstract:
Advancement in nanotechnology and its extensive utilization has raised concerns
about the effects of engineered nano-materials in agriculture and environment. The aim of
present study was to assess the physiological responses of wheat and lettuce to exposure of
0, 20, 40, 60, 80, 100 mg TiO2 nanoparticles (TNPs) kg-1
of soil. The effects of TNPs were
investigated on the phytoavailability of phosphorus (P), root and shoot lengths, total fresh
and dry biomass, chlorophyll content, H2O2 generation and DNA damage. The wheat and
lettuce plants were exposed to TNPs for 60 and 75 days, respectively. It was found that
uptake of P increased significantly (p<0.05) with decreasing pH as compared to control by
lettuce, whereas wheat accumulated the maximum concentration of P at 60 mg kg-1
of TNPs.
An increase in root and shoot lengths (35.3% and 39.2%), total fresh and dry biomass (46%
and 52%), chlorophyll content (68%) and H2O2 generation (40%) was observed in lettuce
at the highest level of TNPs applied as compared to the control. However, for wheat, the
maximum increase in root and shoot lengths (42.2% and 35.7%), total fresh and dry biomass
(60% and 72%) and chlorophyll content (29.7%) was observed at 60 mg kg-1
concentration
level of TNPs in comparison with the control followed by a decrease at higher TNPs
treatment levels. The results confirmed that wheat could not tolerate high concentrations
(80 and 100 mg kg-1
) of TNPs due to overproduction of H2O2 content (80%) and DNA
damages (40.5%). This study suggested the need to further investigate the possible
consequences and effects of applying nanoparticles on agricultural crops.
