Abstract
This study investigates (i) in planta uptake and transfer of magnetic nanoparticles (MNPs) in the plant body and (ii) impact of MNPs on plant nutrition. For these purposes, barley (Hordeum vulgare L.) seedlings were subjected by varied MNP doses (125 to 1000 mg L-1 of CoNd0.2Fe1.8O4) for 3 weeks in a hydroponic system. Plant tissues (root and leaf) were analyzed by using vibrating sample magnetometer (VSM) and inductively coupled plasma optical emission spectrometer (ICP-OES) techniques to understand MNPs' uptake and translocation in the plant body, and plant nutrition status as well. Elemental composition and magnetic behavior analyses of plant parts proved that MNPs, sized in 8.4 +/- 0.05 nm, are uptaken by the plant roots and led to an increase in iron (Fe), neodymium (Nd), and cobalt (Co) contents of leaves (p < 0.005). However, compared with the untreated control, the amount of some macro- and micro-elements (K, Ca, Mg, Mn, and P) are declined in the leaf by increased MNP doses (p < 0.05). Root-to-leaf translocation index (%) of the elements were dramatically decreased, except the one for Fe which increased from 25 (control) to 55% in 1000 mg L-1 condition. Accordingly, MNPs are uptaken by the plant roots and transferred to the leaves. However, it suppresses the translocation of essential nutrients. This finding shows that MNPs used in this study is detrimental for plant mineral nutrition. Besides, the VSM technique coupled with ICP-OES enables to track MNPs in the plant body.