Effects of metal nanoparticles of iron, copper and cobalt on the growth of nitrogen-fixing bacterium Sinorhizobium fredii T14 and nodulation in soybean roots

Soybean is a high valuable crop of Vietnam and many other countries. The ability soybean plants in nitrogen fixation soil improvement attributed to their symbiosis with different rhizobia the root nodules. It has been well documented that members genus Rhizobium are most effective nodulation legumes. Recently, oder minimize undesired accumulation agro-chemicals metal salts soil, nanotechnology products have intensively studied applied as nanofertilizers. In this report, effect nanoparticles iron, cobalt copper on vitro growth fixing bacterium Sinorhizobium fredii T14 DT26 was studied. cultures S. T14, nano Fe at final concentrations 2, 5, 10, 25 50 ppm did not affect growth, but latter reduced 20, 35 46% 100, 250 500 ppm, respectively. No inhibition observed Co below 10 while it 73% ppm. Nano Cu seemed significant adverse showing 23, 68 100% production extracellular polysaccharide by affected drastic decrease occurred presence Cu. Laboratory experiments showed all three metals extremely low concentration 2 significantly increased number nodules roots enhanced plant growth.