تاثیر ذرات نانونقره بر فلور میکروبی خاک در بازه‌‌های زمانی گوناگون رشد پنبه

Nanosilver particles have different applications however there is little information about their toxicity on environment. Based on the importance of biosafety studies related nanosilver particles and their effects on biodiversity of soil microflora; we studied two different colloidal formulations (2 nm and 20 nm) of nanosilver. First, high concentrations (0, 100, 250, 500, 1000 and 2000 ppm) of nanosilver particles were studied on soil bacterial of cotton field and according to the inhibition of bacterial growth by both formulations, low concentrations (0, 5, 10, 25 and 50 ppm) of nanosilver particles were studied during 4 months, at second phase. Results showed that bacterial population affected by both particle size and concentration of nanosilver. We found that decreasing of microbial flora by both particle size and concentration of nanosilver was stable during all plant growth periods. Bactericidal or bacteriostatic activities of nanosilver particles were evaluated with 0, 5, 10, 25 and 50 ppm concentrations of nanosilver. Results showed that all concentration of both nanosilver formulations had bactericidal activity that was increased by increscent of nanosilver concentration. This study showed that both of particle size and concentration can influence soil bacterial flora during plant growth periods. So, studies regarding optimum doses as well as nanosilver toxicity can decrease undesired environmental effects on beneficial parts of soil microflora.