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Copper phytoextraction mediated by Medicago sativa L. (alfalfa) plants plus soil acidification, biodegradable chelant and oomycete combination

Daniela Trujillo: Pontificia Universidad Católica de Valparaíso

<div>High levels of soil copper concentrations cause toxicity on plants determining an abiotic disease. Phytoextraction arises as a possible strategy for cleaning contaminated soils with copper. However, the efficiency of the process is low due to the low biomass generation of plants growing in contaminated soils, the low availability of copper in the soil solution and the limited copper translocation from plant roots to the canopy. The purpose of this work was to search for a methodology to improve phytoextraction efficiency of alfalfa plants, with soil acidification plus a biodegradable chelator and the action of an oomycete. A pot experiment was carried out in a greenhouse for 135 days and harvested twice with a completely random design. Each experimental unit was one alfalfa plant growing in a 3 L pot with soil containing 650 ppm copper. Oomycete and phosphoric acid (H<sub>3</sub>PO<sub>4</sub>) plus the chelator methylglycliciacetic acid (MGDA) for corresponding treatments were added individually and in combination, in addition to a control. Each treatment had 8 replicates. The combination of H<sub>3</sub>PO<sub>4</sub> plus MGDA and oomycete increased 63.1 and 64.6 times copper concentration at alfalfa canopy in the first and second harvest respectively with respect to control. Therefore, the combined treatment is a feasible technology for soil copper phytoextraction.</div>