Concentration and localization of arsenic in roots and nodules in peanut plants exposed to arsenic aggravated by flooding episodes

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

Congreso; XXX Reunión Latinoamericana de Rizobiología. V Conferencia Latinoamericana de Microorganismos Promotores del Crecimiento Vegetal.; 2021

Peanut is an agriculturally valuable plant with a world-wide distribution. In Argentina, arsenic (As) contamination constitutes a problem, since the production of peanut is in Córdoba province, where 90% of the groundwater contains high As which is accompanied by flooding episodes. The aim of this work was to determine i) the concentration of As and phosphorus (P), sulphur (S), chlorine (Cl), potassium (K), calcium (Ca), iron (Fe) and zinc (Zn) in roots and nodules of peanut plants using X-ray fluorescence, and ii) the localization of these elements at tissue level using quantitative micro-particle induced X-ray emission. Peanut plants were grown for 30 days in a sand-perlite (2:1) mixture devoid or containing 3 µM As. Seven days post-emergency, plants were inoculated. Then, plants were distributed in four different groups for 8 days before harvest: control (C), flooding (F), As, and the combination As/F. In roots, As concentrations were lower in the As/F treatment compared to As treatment, while the opposite was observed in nodules. As in roots was mainly allocated to the vascular tissue and rhizodermis. Within the vasculature, As was accumulated in the parenchyma cells, which contained less concentration of P, Cl, K and Ca but more S than xylem and phloem. Cl, Fe and Zn levels were increased in As-treated plants and P and S decreased. As/F treatment reduced K, Cl and Mn content. In nodules, As was equally distributed and most of the analysed essential elements were reduced while in As/F this result was reversed, except Fe, Mo and Mn whose concentration was severely affected in the As and the combined treatment. This detailed analysis of the concentration and the localisation in parts and tissues of peanuts will significantly contribute to the knowledge of the disturbances caused by As and flooding in this valuable crop.