Fig. 7

Schematic representation of the uptake and translocation mechanisms of carbon nanotubes (CNTs) via different routes in crops. A Different routes of entry of CNTs into crops, including foliar and root entrance. B CNT movement in several organs of plant leaves and roots. C Transmission electron microscopy characterization of multi-walled carbon nanotube (MWCNT) uptake in broccoli plants cultivated for 7 days with MWCNTs (10 mg/L) in nutrient solution. Arrows point to MWCNTs in the intercellular space, vacuole, and cytoplasm of the roots and stems [54]. D Spectroscopic characteristics of individual CNTs to detect CNT aggregates in tomato flowers using Raman scattering [53]. E Raman spectroscopy to identify MWCNT translocation inside soybean plants. Slices of various plant tissues, including the leaves, stems, roots, and seeds, were prepared and studied using Raman spectroscopy and point-by-point mapping of selected locations [229]. F Raman spectroscopy to identify MWCNT translocation inside maize plants. Slices of various plant tissues, including the tassels, leaves, stems, roots, and seeds, were prepared and studied with Raman spectroscopy using point-by-point mapping of selected locations [229]