摘要
Emerging contaminants like metal nanoparticles get introduced into soil through different routes.Toxic effects of these contaminants on plant growth-promoting bacteria(PGPB),which influence plant productivity,can be detrimental to soil health.Titanium dioxide is one of the most produced nanomaterials in the world and therefore potentially the most released nanoform in soil.The objective of this study was to evaluate the toxic effects of titanium dioxide nanoparticles(TiO2 NPs)on plant growth-promoting bacteria.Three types of PGPB,viz.,nitrogen fixers,phosphate solubilizers and biofilm formers were exposed to TiO2 NPs.Our results suggest that direct contact of the bacteria with these NPs is inhibitory as compared to when these bacteria are growing in laboratory nutrient media in the presence of NPs.The inhibitory effect did not follow a linear dose response but instead showed a pronounced step response.Soils with their varying characteristics may not afford the same protection to bacteria as laboratory nutrient media and thus TiO2 NPs may cause some sensitive PGPB to disappear from soil.The resultant shift in bacterial community composition may affect ecosystem functioning.
基金
the University Grants Commission(UGC)of the Government of India(Minor research grant:47-584/13(WRO)).
