{"status":"OK","msg":"Details loaded!","presentation":{"id":62,"title":"UPTAKE OF ZINC (II) OXIDE NANOPARTICLES BY COMMOM BEAN SEEDS: A \u00b5-XRF AND \u00b5-XANES BASED STUDY ","abstract":"Nanomaterials present unique properties that strongly differ from those exhibited by bulk materials. Such singular features may be used to boost crop production. In this context, our group has been investigating the absorption, transport and metabolism of nanomaterials by plants. The present work has addressed the effects of nano ZnO on the germination of seeds of Phaseolus vulgaris. Seeds were soaked for 20 min in aqueous dispersions of 20, 40 and 60 nm ZnO at 1000 mg L-1. Germination was monitored during five days. The results showed that, compared to control seeds, 20 nm particles promoted the radicle development, whereas 40 nm and 60 nm prevented it. Aiming at understanding such effects, we have employed X-rays to monitor Zn behaviour. EDXRF analysis showed that Zn penetrates the seed coat reaching the embryo. For treated seeds Zn level goes from thousands to hundreds of mg kg-1 at the coat and embryo, respectively. In control seeds, it remains at tens of mg kg-1regardless the location. Figure 1a shows the distribution of Zn at the seed treated with 60 nm ZnO. The map indicates a gradient from the outer to inner region, Zn is mainly present at coat. \u00b5-XANES was recorded at locations shown by Figure 1b. Conversely to control seed, Zn chemical species depends on the tissue nature. At the external part of seed coat, Zn remains as ZnO. At the middle of the coat it is mixture of ZnO + Zn-malate and at embryo it is found as Zn-hystidine + Zn-phytate. The seeds treated with 20 nm presented an important fraction of Zn-hystidine at the seed coat. Thus, at the current stage of our research, the results indicate that Zn-hystidine complex could be more beneficial for the seeds development. \r\n \r\nFigure 1 \u2013 (a) \u00b5-XRF image showing Zn distribution (30 \u00b5m beam), (b) Magnified optical image highlighting the spots where \u00b5-XANES (12 x 25 \u00b5m2 beam) were recorded and (c) Normalized Zn-K \u00b5-XANES spectra. Seeds treated with 60 nm particles.\r\nAcknowledgement: This project has been funded by FAPESP Young Investigators Awards 2015\/05942-0 and FAPESP Multi-User Equipment Grant 2015\/19121. The \u00b5-XANES measurements were performed at XRF beamline at LNLS, CNPEM. We are grateful to Dr. Carlos A. Perez and Douglas Galante for their assistance during beamtime. \r\n","keywords":"Nanomaterials; Agriculture; Micro-Fluorescence; Micro-XANES; Synchrotron","status":"active","sarx_st":"accepted","user_id":52,"created_at":"2016-06-15 16:52:35","updated_at":"2016-08-20 12:23:16","filename":"UPTAKE OF ZINC (II) OXIDE NANOPARTICLES BY COMMOM BEAN .pdf","mode":"oral","sarx_code":"14_O-XRF","poster_group":null,"file":"b6a79b085c546eacb3803a4967985ab4.pdf","author":"Hudson Wallace Pereira de Carvalho","affiliation":"Asst. Prof. \/<\/b> Universidade de S\u00e3o Paulo \/<\/b> Brasil","user":{"id":52,"name":"Hudson Wallace Pereira de Carvalho","degree":"Asst. Prof. ","email":"hudson@cena.usp.br","username":"hudson@cena.usp.br","confirmed":1,"confirmation_code":null,"created_at":"2016-04-05 12:08:25","updated_at":"2016-04-05 12:14:01","sarx":1,"affiliation":"Universidade de S\u00e3o Paulo","address":"Av. Centen\u00e1rio, 303","zipcode":"13416000","state":"S\u00e3o Paulo","phone":"1934294737","fax":null,"city":"Piracicaba","country":"Brasil","status":"active","is_admin":0,"category":"professor","school":0,"icdd":0}}}