Uptake, translocation, transformation and physiological effects of nanoparticles in plants

Nanoparticles (NPs) have large potential to increase the efficiency of agrochemicals, crop production and soil health; however, their mechanism of uptake and their interaction with plant and environment is still not known properly. Chemical fertilizers that are used to supply nutrients to crops globally are detrimental to both humans and environment. Nanotechnology has a significant role in agriculture mainly to supply fertilizers and pesticides. The present review explores the progress on uptake, including the foliar and root exposure of NPs, various physiological barriers and factors affecting the uptake of NPs along with their translocation pathways via xylem and phloem. We have also emphasized on the transformation of NPs in soil, at the plant interface and inside the plant and effects of phyllosphere and rhizosphere processes on the transformation and the uptake of transformed NPs. We have also reviewed the physiological effects of NPs in improving growth, yield and enhancing stress tolerance in higher plants and discussed the phytotoxicity of NPs. Overall, this work has reviewed the present knowledge on the uptake, translocation and transformation of NPs and their interaction with higher plants. The perspectives for future research are outlined to ensure sustainability of NPs in agricultural practices.