Uptake, Translocation And Physiological Effect Of Iron Oxide Nanoparticles By Corn Plants

In recent years, with the rapid development of nanotechnology, nanoparticleshave been widely applied to sorts of fields, like the life of sciences, environment,energy, consumer goods, medicine, etc. Currently it causes widespread interest inusing nanotechnology to improve crop yield and quality. Such as nano-basedpesticides and fertilizer can provide good prospects for sustainable development ofagriculture. Some researches have already reported that nanoparticles can promoteseed germination and root growth, and enhance photosynthesis synthesised andanti-oxidative stress capacity together with some biological effects of chlorophyll inplants. Whereas, the mechanism of these positive biological effects remains unclear,and meanwhile, the nano-safety for the extensive application of them to plants is notverified. Therefore, the in-depth study on how nanoparticles affect the biologicaleffect and action mechanism of nanoparticles becomes the key to solve theseproblems.As based on the fact that nanoparticles are able to enter into the body of theplant, iron oxide nanoparticles is expected to be applied as iron-supplementing agentin agriculture, since the conventional one own shortcomings, such as such as lowefficiency, great loss and so on. Now, it has been found that iron oxide nanoparticlesat proper concentrations could boost seed germination and root growth added with thepromotion of chlorophyll synthesis. However, the mechanism of these positivebiological effects remains unclear, and meanwhile, making sense of accumulation andtransport mechanisms are the basis for the study of its impact on the biological effectsof the plant. In this study, labelling technology of fluorescent species was applied toinvestigate the transportation pathway of nanomaterials and their accumulationbehaviors in plants. Fluorescein isothiocyanate (FITC)-conjugated γ-Fe2O3nanoparticles were prepared through a strategy of siloxane coupling. The resultsverified almost no changes in the crystalline structure and size of the nanoparticlesafter the FITC-conjugation process. Hence, such fluorescence-labelled γ-Fe2O3nanoparticles were used to investigate their uptake behavior by watermelon. So theentry and apoplastic pathway were disclosed, namely the nanoparticles firstly penetrated into the root, and then migrated among cells from epidermis toendodermis.Although we have revealed the mechanism-the way iron oxide nanoparticlescoming to the root, this studies is still not enough for researching the effect of the irontoward plants. Therefore, this study selected maize as research object to explore thephysiological effects of iron oxide nanoparticles on it. The result depicted thatnano-Fe2O3at the concentration of20×10-7mg/L better contribute to the maizeseed germination promotion and root growth, and chlorophyll synthesized, and alsofound that that oxidative stress happened in the plant treated with nano-Fe2O3, andcan stimulated the self-protection mechanism and thus reduce damage to the body。While exploring the transportation pathway of nano-Fe2O3and their accumulationbehaviors by corn, we found that nano-Fe2O3mainly accumulated in the roots, andtransport from the epidermis into the cortex mainly through the apoplastic pathway.In addition, it found that nano-Fe2O3may penetrate into maize cells by endocytosispathway, and mostly enriched around the surface of the nucleus. This laid thefoundation for further assess the biological effects of nano-Fe2O3on plants in order toapply it safe and efficient in agricultural.