title: Auxin effects on Pb phytoextraction from polluted soils by Tegetes minuta L. and Bidens pilosa L.: Extractive power of their root exudates.
abstract: The principal impediment for Pb uptake by plants is the Casparian strip in roots. It prevents metals reaching the xylem, thereby hampering translocation to the aerial organs. In the root apices, young root cells have thin cell walls and the Casparian strip is not completely developed, which could facilitate Pb uptake by roots at these vulnerable points. However, as the phytotoxic effects of Pb reduce root growth and enhance suberization, entry of Pb into the plant is avoided. We propose that the application of root growth promotors could be an important complement in the phytoextraction of Pb from polluted soils, due to their effects on produced biomass, Pb toxicity, and root exudate production. A greenhouse experiment was carried on to evaluate the auxin application effect on the Pb uptake of Bidens pilosa and Tagetes minuta. These species were sensitive to auxins, but the phytotoxic effect of Pb was not reversed by this treatment. Root exudates capable of extracting Pb were produced only when the species were grown in highly polluted soils, indicating a behavioral response to Pb exposure which is desirable for phytoremediation.
authors.affiliation: Multidisciplinary Institute of Plant Biology, Pollution and Bioindicator Section, Faculty of Physical and Natural Sciences, National University of Córdoba, Av. Vélez Sársfield 1611, X5016CGA Córdoba, Argentina. Electronic address: mjulietasalazar@gmail.com.
authors.forename: María Julieta
authors.initials: MJ
authors.lastname: Salazar
authors.affiliation: Multidisciplinary Institute of Plant Biology, Pollution and Bioindicator Section, Faculty of Physical and Natural Sciences, National University of Córdoba, Av. Vélez Sársfield 1611, X5016CGA Córdoba, Argentina.
authors.forename: Judith Hebelen
authors.initials: JH
authors.lastname: Rodriguez
authors.affiliation: Multidisciplinary Institute of Plant Biology, Pollution and Bioindicator Section, Faculty of Physical and Natural Sciences, National University of Córdoba, Av. Vélez Sársfield 1611, X5016CGA Córdoba, Argentina.
authors.forename: Carolina Vergara
authors.initials: CV
authors.lastname: Cid
authors.affiliation: Multidisciplinary Institute of Plant Biology, Pollution and Bioindicator Section, Faculty of Physical and Natural Sciences, National University of Córdoba, Av. Vélez Sársfield 1611, X5016CGA Córdoba, Argentina.
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Pignata
mesh_terms: D031176:Bidens / Q000187:drug effects* / Q000378:metabolism; D001673:Biodegradation, Environmental; D007210:Indoleacetic Acids / Q000494:pharmacology*; D007854:Lead / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism*; D031686:Tagetes / Q000187:drug effects* / Q000378:metabolism
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D012989:Soil Pollutants; D007854:Lead; C030737:indoleacetic acid
keywords: Bidens pilosa; Lead soil pollution; Phytohormones; Root exudates; Tagetes minuta