Neue Befunde zur Aufnahme von Nanopartikeln durch Pflanzen
Die vermehrte Anwendung von Nanotechnologie führt dazu, dass vermehrt Fragen nach der Toxizität dieser Substanzen geklärt werden müssen. Bis anhin haben sich jedoch nur wenige Forscher mit der Phytotoxizität von Nanomaterialien beschäftigt; es ist daher nicht bekannt, ob Pflanzen Nanopartikel aufnehmen und transportieren können. Eine kürzlich publizierte Studie kam zu dem Ergebnis, dass ZnO-Nanopartikel in bestimmten Konzentrationen durch Wurzelzellen von Pflanzen absorbiert werden, deren Zellwände zerstören und das Keimwachstum hemmen können. [Artikel in englischer Sprache]
As the discussion about potentially undesired side effects of engineered nanoparticles heats up, research on toxicological effects of nanomaterials gets increasing attention. Nanotoxicology is quickly being established as a new field, with its major focus on human and animal studies. However, very few studies have been conducted to assess the toxicity of nanomaterials to ecological terrestrial species, particularly plants. So far, the mechanisms of nanoparticle phytotoxicity – the ability to cause injury to plants – remain largely unknown and little information on the potential uptake of nanoparticles by plants and their subsequent fate within the food chain is available.
In order to develop a comprehensive toxicity profile for engineered nanoparticles – including the entire life cycle of these materials from creation to disposal – a thorough understanding of the phytotoxicity mechanism and uptake potential by plants, and the subsequent impact on human and environmental health through food chains, is required.
In a new study, scientists used a hydroponic culture system to examine plant cell internalization and possible upward translocation of ZnO nanoparticles. The dissolution of ZnO nanoparticles and its contribution to the phytotoxicity were also investigated. Ryegrass (Lolium perenne) was used as a model plant for its wide distribution and common use in phytotoxicity study.
The experiments performed in this study took place in Petri dishes to examine the inhibition of ZnO nanoparticles on seedling root elongation; plant uptake and rhizosphere dissolution of the ZnO were not investigated.
"Our research revealed that ZnO nanoparticles at certain concentrations could adsorb onto ryegrass root surface, damage root tissues, enter root cells, and inhibit seedling growth" Dr. Baoshan Xing, a professor in the Department of Plant, Soil & Insect Sciences at the University of Massachusetts, tells Nanowerk. "We also found that the phytotoxicity of ZnO nanoparticles could not primarily come from their dissolution in the bulk nutrient solution or the rhizosphere."
Xing explains that the current study was aimed at examining any potential eco-effect of nanoparticles in higher plants and to answer two questions: One is whether plants can uptake and transport nanomaterials. The other is the contribution of dissolution to the phytotoxicity of metal-based nanomaterials.
Xing together with Dr. Daohui Lin from the Department of Environmental Science at
Quelle: Nanowerk