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

BIANUCCI, ELIANA; PONGREAC, P; HROVAT K; VOGEL-MIKU K; PELICON P; KELEMEN M; VAVPETIC P; FURLAN, ANA LAURA; POSCHENRIEDER C

Congreso; 18th INTERNATIONAL CONFERENCE ON NUCLEAR 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 plant available form of essential phosphorus (PO43-). Therefore, when arsenate reaches the rhizosphere, it is inadvertently taken up by the roots, transported within the plant and may enter edible seeds. Moreover, exposure to As and flooding can negatively affect the uptake of essential elements and could cause redistribution of these elements within the plant. The aim of this work was to study the uptake and distribution of As in different parts of peanut and to determine the tissue-specific localization of As in roots and nodules under non-flooded and flooded conditions. Nodule formation was induced by inoculation with the beneficial bacterium Bradyrhizobium sp. SEMIA6144 and plants were grown under controlled conditions for 45 days and exposed to the four treatments (Control, As, flooding and As&flooding). Using X-ray fluorescence total concentration of elements were determined. The highest concentration of As was detected in roots, followed by nodules, while the concentration of As detected in stems and leaves was significantly lower. Using quantitative micro particle- induced X-ray emission (Jožef Stefan Institute, Slovenia), allocation of As was determined at the tissue level in cross-sections of roots and nodules. Spectra were fitted, and quantitative distribution maps were generated using GeoPIXE software [2]. The detailed analysis of the localization 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.