Studies On The Transportation Of ZnO Nanoparticles In Celery Stem With Resonant Raman Scattering

Studies have shown that nanoparticles do have certain toxicity on organisms. Generally,the interaction process of nanoparticles with biological systems mainly involves three steps,uptake, translocation, and accumulation. Currently, the translocation of nanoparticles in plantshave been researched in several studies with CeO2, Fe3O4nanoparticles, the methods used aremainly radioactive tracer method, vibrating sample magnetometer (VSM) measurementmethod. Due to the limited detection sensitivity, these studies found no obvious signs ofnanoparticles in the stems of plants. In this thesis, taking advantage of the high sensitivitycharacteristics of resonant Raman scattering, we studied the translocation of ZnOnanoparticles in celery stems, successfully detected the resonant Raman scattering signal ofZnO nanoparticles in celery stem.Firstly, researches on the biological effects of nanoparticles, especially the advances ofnanotoxicology were briefly reviewed, the current status of the research of translocationprocesses of nanoparticles in plants were summarized. On these basis, the translocation ofZnO nanoparticles, which were most widely used nanomaterial, was studied in celery stemwith resonant Raman scattering. ZnO nanoparticles were prepared with sol-gel method with adiameter of about3-5nm, the particle size was relatively small and morphology was uniform.ZnO nanoparticles were dispersed in deionized water by ultrasonic oscillation to formulate30mg/L suspension. Celeries were cultured in this suspension. Celery cultuered in deionizedwater was used as control. Before resonant Raman scattering measurement, celeries weretreated with dilute acetic acid and washed with distilled water several times to remove ZnOnanoparticle contamination on the surface of celery stalk. Resonant Raman scattering wascarried out on the cross-section of celery stem and vascular bundles. Obvious resonant Ramanscattering signals of ZnO nanoparticles were detected in the vascular of celery cultured inZnO nanoparticle suspension, showing that ZnO nanoparticles indeed existed in the vascularbundles. On the transverse section of celery stem, resonant Raman scattering signals weredetected only on the cross section of the vascular bundle, no ZnO Resonant Raman scatteringsignal was detected on the other parts of cross-section of the stem. Whereas in the control, noZnO was detected. These results indicated that, ZnO nanoparticles translocate upward throughvascular bundles in celery stalk, while other parts of the stem have no the ability totranslocation ZnO nanoparticles.