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The use of nanoparticles (NPs) in numerous products and their potential accumulation causes major concern for humans and the environment. Until now, the uptake of NPs in plant tissue was mostly shown under greenhouse conditions at high doses and short exposure periods. Here we present results on the uptake of particulate silver (Ag) and cerium dioxide (CeO2) in the tissue of Triticum aestivum, Brassica napus and Hordeum vulgare, after exposure to sewage sludge treated with nano-Ag (NM300K at 1.8 and 7.0 mg/kg sludge per dm soil) and nano-CeO2 (NM212 at 10 and 50 mg/kg sludge per dm soil). All plants were cultivated in a rural area near the German town Schmallenberg according to the common regional crop rotation on outdoor lysimeters. The highest concentration measured was 86.4 mg/kg for Ag (Hordeum vulgare), and 94 mg/kg for Ce (Triticum sativum). Analysis of plant samples revealed the presence of Ag mainly in its ionic form. However, the occurrence of nano- and larger sized particles of Ag and CeO2 was observed as well. Quantitative shares of the particulate fraction of the total element concentration were estimated with up to 22.4% for Ag and with up to 85.1% for CeO2. A high abundance of particle agglomerates in the phloem suggests upward transport of the nanoparticles to other plant parts. A small number of agglomerates in the xylem suggests a downward transport, and subsequent accumulation in the root phloem. Exemplary investigations of Brassica napus root exposed to nano-CeO2 revealed no accumulation of the pristine material in the cell nucleus, however, CePO4 was found. The presence of this substance points to a dissolution of the low soluble CeO2 in planta and subsequent precipitation. Furthermore, for the first time, mixed NP-salt agglomerates, composed of Ca3PO4+ and K3SO4+ NPs, could be observed within Brassica napus root tissue.
This article was published in the following journal.
Name: Environmental science & technology
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Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.
Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.
A cone-shaped structure in plants made up of a mass of meristematic cells that covers and protects the tip of a growing root. It is the putative site of gravity sensing in plant roots.
Drugs that inhibit the transport of neurotransmitters into axon terminals or into storage vesicles within terminals. For many transmitters, uptake determines the time course of transmitter action so inhibiting uptake prolongs the activity of the transmitter. Blocking uptake may also deplete available transmitter stores. Many clinically important drugs are uptake inhibitors although the indirect reactions of the brain rather than the acute block of uptake itself is often responsible for the therapeutic effects.
A genus of gram-negative, rod-shaped bacteria in the family PHYLLOBACTERIACEAE. They are able to invade root-hairs of a wide range of plants, inciting the production of PLANT ROOT NODULES.