Uptake and tissue-specific localization of arsenic in roots and nodules in peanut

BIANUCCI ELIANA; PAULA PONGREAC; KATARINA HROVAT; KATARINA VOGEL-MIKU?; PRIMO? PELICON; MITJA KELEMEN; PRIMO? VAVPETIč; ANA FURLAN; CHARLOTTE POSCHENRIEDER

Congreso; 18TH INTERNATIONAL CONFERENCE ON NUECLEAR MICROPROBE TECHNOLOGY AND APPLICATIONS; 2022

Arsenic (As) is toxic to plants and animals. Flooding of agricultural land with As-rich groundwaterincreases the risk of As mobility in the food chain and has become a significant threat. One suchsituation is with peanut (Arachis hypogaea L.), an agriculturally valuable crop in Córdoba provincein Argentina, where i) several cropping areas contain high concentration of As and ii) occasionalflooding episodes increase As-containing groundwater level [1]. Both circumstances could lead to areduction on peanut yield and increase the possibility of seed contamination with As. Arsenate(As(V); AsO43-), a form of As, is particularly problematic, because it is chemically similar to the plantavailableformof essentialphosphorus(PO43-).Therefore,whenarsenatereachestherhizosphere,itisinadvertentlytakenup bythe roots,transportedwithinthe plantand mayenteredibleseeds.Moreover,exposureto Asand floodingcannegativelyaffectthe uptakeof essentialelementsandcouldcauseredistributionof theseelementswithinthe plant.Theaimofthisworkwasto studytheuptakeanddistributionof Asindifferentpartsof peanutand to determinethe tissue-specificlocalizationofAsinrootsand nodulesundernon-floodedand floodedconditions.Noduleformationwasinducedbyinoculationwiththe beneficialbacteriumBradyrhizobiumsp.SEMIA6144and plantsweregrownundercontrolledconditionsfor45daysandexposedtothefourtreatments(Control,As,floodingandAs&flooding).UsingX-rayfluorescencetotalconcentrationof elementsweredetermined.ThehighestconcentrationofAswasdetectedinroots,followedbynodules,whiletheconcentrationofAsdetectedinstemsandleaveswassignificantlylower.Usingquantitativemicroparticle-inducedX-rayemission(JožefStefan Institute, Slovenia), allocation of As was determinedat the tissue level in cross-sections of roots and nodules. Spectra were fitted, and quantitativedistribution maps were generated using GeoPIXE software [2]. The detailed analysis of thelocalization and distribution of As in different parts and tissues of peanut plants will provide an insight into tissue-specific disturbances caused by As and flooding in this agriculturally important crop.