LAUSR

Loss of biodiversity and accumulation of contaminants in urban soils and water bodies cause serious issues in metropolitan areas. Matanza - Riachuelo river basin (metropolitan area of Buenos Aires - Argentina) is one of the most environmentally degraded regions in the world. Senecio bonariensis (Asteraceae) grows in the periodically flooded soils of this wetland. This plant concentrates potentially toxic trace elements (PTEs) in their tissues and establishes symbiosis with arbuscular mycorrhizal (AM) fungi that collaborate with PETs phytostabilization in soils. The objective of this work was to evaluate tolerance and stress alleviation of AM colonized S. bonariensis when transplanting and exposing to highly polluted environmental conditions of the river basin. Plants were initially inoculated with different AM strains and maintained in greenhouse conditions. After 6 months, they were transplanted to the field. These plants showed a more equal distribution between shoot and root biomass production, in comparison with field spontaneous S. bonaerensis plants. Plants in earlier contact with native soil inoculum showed positive correlation with the phosphorus content and significant increase of vesicles frequency. Otherwise, plants belatedly contacted with native inoculum in the field (control) showed a higher catalase level, positively correlated with the total colonization frequency and chlorophyll content. The ability to establish symbiosis with Rhizophagus intraradices (strain GC3), commonly used in the formulation of biofertilizers, was also analyzed. Plants inoculated with GC3 at the beginning of the assay showed lower colonization and to be less efficient at field. The preservation of spontaneous native plants with ornamental value and bioaugmentation of its associated microbiome can contribute to the stabilization of contaminants in soils. This article is protected by copyright. All rights reserved.