Growth and tolerance of Ilex paraguariensis A. St.-Hil. inoculated with ectomycorrhizal fungi in copper-contaminated soil

Abstract

Copper (Cu) is one of the main heavy metals contaminating the soil. Plants have different behavior in terms of tolerance and toxicity to metals, being able to grow and produce even in soils contaminated with high concentrations. This study aimed to determine the influence of ectomycorrhizal fungi on the growth and tolerance of yerba mate plants grown in soil contaminated with Cu. The design was completely randomized in a factorial arrangement (4x6), with four possibilities of inoculum: without inoculum (control) and three ectomycorrhizal fungi (UFSC-PT116 — Pisolithus microcarpus, UFSC-PT132 — Pisolithus tinctorius and UFSC-SU118 — Suillus cothurnatus), with six Cu doses amended to the soil (0, 80, 160, 240, 320 and 400 mg kg-1 of Cu) in seven replicates. The height of the aerial part, the diameter of the lap, the dry mass of the aerial part and root system, the leaf area, the specific surface area of the roots, the contents of Cu in the aerial and radicular parts, the tolerance index, and mycorrhizal association were assessed. Inoculation of Ilex paraguariensis seedlings with ectomycorrhiza fungi UFSC-PT116, UFSC-PT132, and UFSC-SU118 mitigates the toxicity effect caused by the excess of Cu in the soil. The UFSC-PT116 isolate promoted the highest growth and tolerance of Ilex paraguariensis seedlings under the treatments. In general, the isolates promoted the reduction of Cu toxicity in Ilex paraguariensis plants, being an important alternative to remediate Cu-contaminated areas.