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Abstract Current practices for delivering agrochemicals are inefficient, with only a fraction reaching the intended targets in plants. The surfaces of nanocarriers are functionalized with sucrose, enabling rapid and efficient foliar delivery into the plant phloem, a vascular tissue that transports sugars, signaling molecules, and agrochemicals through the whole plant. The chemical affinity of sucrose molecules to sugar membrane transporters on the phloem cells enhances the uptake of sucrose‐coated quantum dots (sucQD) and biocompatible carbon dots with β‐cyclodextrin molecular baskets (suc‐β‐CD) that can carry a wide range of agrochemicals. The QD and CD fluorescence emission properties allowed detection and monitoring of rapid translocation (<40 min) in the vasculature of wheat leaves by confocal and epifluorescence microscopy. The suc‐β‐CDs more than doubled the delivery of chemical cargoes into the leaf vascular tissue. Inductively coupled plasma mass spectrometry (ICP‐MS) analysis showed that the fraction of sucQDs loaded into the phloem and transported to roots is over 6.8 times higher than unmodified QDs. The sucrose coating of nanoparticles approach enables unprecedented targeted delivery to roots with ≈70% of phloem‐loaded nanoparticles delivered to roots. The use of plant biorecognition molecules mediated delivery provides an efficient approach for guiding nanocarriers containing agrochemicals to the plant vasculature and whole plants. 

If agricultural plants are exposed to carbon nanotubes (CNTs), they can potentially take up the CNTs from growth media and translocate them to their different tissues. In addition, agricultural application of CNTs recently attracted increasing attention, as they could promote germination, enhance crop yield, and exhibit other benefits. For evaluating the environmental effects of CNTs and optimizing their agricultural application, it is essential to quantify CNTs in plant tissues. In this study, pristine (p-) and carboxyl-functionalized (c-) multiwall CNTs (MWCNTs) were extracted from plant tissues by a sequential digestion with nitric acid (HNO 3 ) and sulfuric acid (H 2 SO 4 ). The extracted MWCNTs were stabilized with nonionic surfactant Triton X-100 and analyzed with ultraviolet-visible (UV-vis) spectroscopic analysis to measure the concentration of the MWCNTs in plant (lettuce) tissues. The MWCNT concentration was linearly correlated with the absorbance at 800 nm. The detection limit for p- and c-MWCNTs was achieved at 0.10–0.12, 0.070–0.081, 0.019–0.18 μg mg −1 for leaf, stem, and root tissues, respectively. The developed method was applied for lettuce ( Lactuca sativa , cv. black seeded Simpson) hydroponically grown with 5, 10, 20 mg L −1 of p-MWCNTs and c-MWCNTs in the culture solution. We detected 0.21 ± 0.05–4.57 ± 0.39 μg mg −1 p-MWCNTs and 0.20 ± 0.17–0.75 ± 0.25 μg mg −1 c-MWCNTs in the lettuce roots, positively correlated with the dose of CNTs in solution. We have developed a method for rapid quantification of CNTs in plant tissues using a widely-accessible technique, which can enable reliable analysis of CNTs in plant tissues and provide critical information for evaluating the environmental implications and managing agricultural application of CNTs.