Gibberellic acid, kinetin, and the mixture indole-3-acetic acid-kinetin assisted with EDTA-induced lead hyperaccumnulation in alfalfa plants.
There are a few plant species considered potential hyperaccumulators for heavy metals, particularly lead (Pb). In this study, alfalfa plants grown in hydroponics were exposed to Pb at 40 mg/L, ethylenediaminetetraacetic acid (EDTA) equimolar to Pb, and 1, 10, and 100 microM concentrations of the phytohormones indole-3-acetic acid (IAA), gibberellic acid (GA), and kinetin (KN) and a mixture of IAA and KN at 100 microM each. Metal quantification by inductively coupled plasma/optical emission spectroscopy demonstrated that plants treated with Pb/EDTA plus KN at 1, 10, and 100 microM increased the Pb concentration in alfalfa leaves (compared to Pb alone) by factors of 17, 43, and 67, respectively, and by factors of 2, 5, and 8, respectively, compared to the Pb/EDTA treatment. The correlation coefficient between the Pb concentration in leaves and the concentrations of KN in the medium was 0.9993. In addition, the leaves of plants exposed to a Pb/EDTA/100 microM IAA-KN mixture had approximately 9500 mg of Pb/kg of dry weight, demonstrating that non-Pb hyperaccumulating plants could hyperaccumulate Pb when treated with EDTA and a mixture of IAA-KN. The X-ray absorption spectroscopic studies demonstrated that the absorption and translocation of Pb was in the same oxidation state as the supplied Pb(II).
López
Martha L
ML
Environmental Science and Engineering Ph.D. Program, University of Texas, El Paso 79968, USA.
Peralta-Videa
José R
JR
Parsons
Jason G
JG
Benitez
Tenoch
T
Gardea-Torresdey
Jorge L
JL
D004492:Edetic Acid / Q000494:pharmacology*; D005875:Gibberellins / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology; D007701:Kinetin / Q000494:pharmacology; D007854:Lead / Q000378:metabolism*; D000455:Medicago sativa / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
D005875:Gibberellins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D007854:Lead; C030737:indoleacetic acid; D004492:Edetic Acid; C007842:gibberellic acid; D007701:Kinetin