Bioaccumulation of heavy metals in cucumber plants inoculated with Trichoderma strains (Hypocreaceae) in the Mezquital Valley, Hidalgo, Mexico

Abstract

In the Mezquital Valley, Hidalgo, Mexico, wastewater is often used in agricultural systems which have caused negative environmental effects, such as edaphic heavy metal pollution. Consequently, plants in the area begin to absorb heavy metals. Therefore, the objective of this experiment was to evaluate the effects of Trichoderma harzianum and Trichoderma viride strains on bioaccumulation of Pb, Cd and Cr in inoculated cucumber plants (Cucumis sativus). The soil used in this study contains Pb, Cd and Cr (34.63, 0.24, and 32.32 mg/kg, respectively). In Trichoderma root colonization, the highest measurement was Trichoderma harzianum (100 %). The cucumber plants translocated Pb, Cr, and Cd to their fruits and leaves. Concentrations of Pb and Cd were higher in the basal leaves of the cucumber plant, whereas Cr was more concentrated in the cucumber fruits. Pb was not found in the cucumber skin. For Cd concentration in the skin, the T. harzianum and T. viride treatments at 2.34 × 106 and 2.34 × 106 CFU/mL, respectively, resulted in a 20.2 % reduction of this metal. Trichoderma, with 2.34 × 106 CFU/mL, had the lowest concentration of Cr in the pulp (5.572 mg/kg). No differences were found in metal concentrations in the skin or leaves.