SILVER NANOPARTICLES: TOXIC EFFECT ON MICROORGANISMS AND INTERACTION WITH HIGHER PLANTS
The effects of silver nanoparticles on organisms as well as their further distribution in the ecosystem are not well understood. However, safe implementation of silver-based nano-pesticides in agriculture depends heavily on the answers to these questions. This review article comprises current knowledge from up-to-date literature on the effects of silver nanoparticles on microorganisms in order to gain insight into the mechanisms of nanoparticle toxicity as well as to evaluate toxic concentrations for phytopathogenic bacteria and fungi. The problem of nanosilver accumulation and transport in higher plants is also discussed, which is crucial for wider implementation of nanosilver in agriculture. The comparison between ionic silver and silver nanoparticles of the toxicity in organisms of different hierarchical levels revealed higher «specific toxicity» of silver nanoparticles. It is shown that toxic concentrations vary in the range 10 <sup> -5 </sup> - 10 <sup> -3 </sup> and 10 <sup> -6 </sup> - 10 <sup> -3 </sup> mol/L of silver for bacteria and fungi, respectively. It is also demonstrated that higher plants are able to accumulate and re-distribute silver nanoparticles, and these nanoparticles, in turn, may be toxic to plants in the long term. The effectiveness of accumulation and the effects of nanoparticles on plant metabolism may be dependent on plant species. We conclude that application of nanosilver in phytopathology is a promising way of providing agricultural practice with new advanced plant protection products.