Growth and tolerance of Ilex paraguariensis A.St.-Hil. seedlings grown in copper-contaminated soil

Abstract

Copper (Cu) is a micronutrient necessary for plant development, as it is included in the structure of enzymatic compounds and activators. However, at high soil concentrations it can become toxic to plant metabolism. Thus, the objective of this work was to evaluate the growth and tolerance of Ilex paraguariensis seedlings grown in copper contaminated soil. The study was conducted in a greenhouse of the Department of Forestry Engineering, Federal University of Santa Maria, Campus Frederico Westphalen, RS, between March and September 2018. The seedlings of Ilex paraguariensis used in the experiment were acquired from a nursery located in the municipality of Arvorezinha, RS. The treatments applied were five doses of Cu (0 - control, without addition of copper; 100; 200; 300 and 400 mg Kg-1 of soil). The experiment was carried out in a completely randomized design with 10 replications, each repetition being one plant per pot. After exposure to different treatments under soil cultivation at 150 days, plant height, stem diameter, leaf area, root, stem and leaf dry mass and tolerance index were evaluated. The results showed that the copper doses reduced the seedlings height and stem diameter. The dry mass of all collected partitions showed reduction from the use of 200 mg kg^-1 of soil. The plants submitted to higher Cu (400 mg kg^-1 soil) showed a reduction in leaf area of 64.7% in relation to the control. The species Ilex paraguariensis presented a tolerance index higher than 60% up to 300 mg kg^-1 Cu.

Keywords:
Mate herb; Heavy metal; Micronutrient; Toxicity